# TS Inter second year Maths 2B Concept # These notes cover all the topics covered in the TS I.P.E second year maths 2B syllabus and include plenty of formulae and concept to help you solve all the types of Inter Math problems asked in the I.P.E and entrance examinations.

CONTENT

## 1. CIRCLES

Circle: In a plane, the set of points which are at a constant distance from a fixed point is called a circle. ∗ The fixed point is called centre (C) of the circle and constant distance is called radius(r) of the circle

Unit circle: If the radius of the circle is 1 unit, then that circle is called the unit circle. Point Circle: A circle is said to be a point circle if its radius is zero. A point circle contains only one point in the centre of the circle.  •

(x – h)2 + (y – k)2 = r2

x2 + y2 = r2

⇒ x2 + y2 = r2 is called standard form of the circle.

The general equation of the second degree ax2 + 2hxy + by2 + 2gx + 2fy + c = 0, where a, b, f, g, h and c are real numbers, represent a circle iff (i) a = b ≠ 0 (ii) h = 0 and (iii) g2 + f2 + c ≥ 0

∗ The general equation of the circle is x2 + y2 + 2gx + 2fy + c = 0

∗ The equation of the circle passing through origin is x2 + y2 + 2gx + 2fy = 0.

∗ The equation of the circle whose centre on the x-axis is x2 + y2 + 2gx + c = 0.

∗ The equation of the circle having centre on y-axis is x2 + y2 + 2fy + c = 0.

∗ The circles which have the same centre are called concentric circles.

∗ The equation of the circle concentric with the circle x2 + y2 + 2gx + 2fy + c = 0 is

x2 + y2 + 2gx + 2fy + k = 0.

Note: –

(a) if g2 – c = 0, then A1 A2 = 0 ⇒ the circle touches the x- axis at only one point.

(b)  if f2 – c = 0, then B1 B2 = 0 ⇒ the circle touches the y- axis at only one point.

(c) if g2 – c < 0, then the circle does not meet the x- axis.

(d) if f2 – c < 0, then the circle does not meet the y- axis.

∗ The equation of the circle having the line segment joining A (x1, y1) and B (x2, y2) as a diameter is (x – x1) (x – x2) + (y – y1) (y – y2) = 0.

• The line is called secant line of the circle.
• The line segment is called chard of the circle.
• AB is called the length of the chord.

∗ A chord passing through the centre is called the diameter of the circle.

∗ The angle subtended by a chord on the circumference of at any point is equal. The perpendicular bisector of a chord of a circle is asses through the centre of the circle. ∗ The angle in a semicircle is 900. ∗ The equation of the circle passing through three non-collinear points A (x1, y1), B (x2, y2), C (x3, y3) is Where ci = − (x2 + y2) and i = 1,2,3

∗ centre of the circle is Parametric form:

If P (x, y) is a point on the circle with centre (h, k) and radius r, then

X = h + r cosθ, y = k + r sinθ  0 ≤ θ ≤ 2π.

⇒ A point n the circle x2 + y2 = r2 is taken as (r cosθ, r sinθ) and simply denoted by θ.

Note:

1.  If the centre of the circle is the origin, then the parametric equations are x = r cosθ, y = r, 0 ≤ θ ≤ 2π.
2. The point (h + rcosθ1, k + r sin θ1) is referred to as the point θ1 on the circle having the centre (h, k) and radius r.

Notations:

S = x2 + y2 + 2gx + 2fy + c

S1 = xx1 + yy1 + g(x +x1) + f (y +y1) + c

S11 = x12 + y12 + 2gx1 +2fy1 + c

S12 = x1x2 + y1y2 + g(x1 + x2 ) + f (y1 + y2) + c

Position of a point with respect to the circle: A circle in a plane divides the plane into three parts.
1. The interior of the circle

2. The circumference which is the circular curve.

3. The exterior of the circle.

Power of point:

Les S = 0 be a circle with radius ‘r’ and centre ‘C’ and P (x1, y1) be a point on the circle, then CP – r2 is called the power of point ‘P’ concerning S = 0. • The power of point P (x1, y1) w.r.t. S = 0 is S11.

1. P lies in the interior of the circle ⇔ S11 < 0.
2. P lies on the circle ⇔ S11 = 0.
3. Plies in the exterior of the circle ⇔ S11 > 0.

Secant and tangent of a circle:

The limiting position of the secant line PQ when Q is approached to the point P along the circle is called a tangent to the circle at P.

Length of the tangent: If P is any point on the circle S = 0 and T is any exterior point of the circle, then PT is called the length of the tangent.

Condition for a line to be a tangent:

Note:

Chord joining two points on a circle:

If P (x1, y1) and Q (x2, y2) are two points on the circle S = 0 then the equation of secant line PQ is S1 + S2 = S12.

Equation of tangent at a point on the circle:

The equation of the tangent at the point (x1, y1) to the circle S ≡ x2 + y2 + 2gx + 2fy + c = 0 is S1 = 0.

The equation of the tangent at the point (x1, y1) to the circle x2 + y2 = r2 is xx1 + yy1 – r2 = 0.

Point of contact:

If a straight-line lx + my + n = 0 touches the circle S ≡ x2 + y2 + 2gx + 2fy + c = 0 at P (x1, y1), then this line is the tangent to the circle S = 0. And the equation of the tangent is

(x1 + g) x + (y1 +f) y + (gx1 + fy1 + c) = 0.

∗ The equation of the chord joining two points θ1, θ2 on the circle x2 + y2 + 2gx + 2fy + c = 0 is ∗ The equation of the chord joining the points θ1, θ2 on the circle x2 + y2 = r2 is ∗ The equation of the tangent at P(θ) on the circle x2 + y2 + 2gx + 2fy + c = 0 is ∗ The equation of the tangent at P(θ) on the circle x2 + y2 = r2 is

x cosθ + y sinθ = r.

Normal: The normal at any point P of the circle is the line which is passing through P and is perpendicular to the tangent at P.

• The equation of the normal at P (x1, y1) of the circle S ≡ x2 + y2 + 2gx + 2fy + c = 0 is

(x – x1) (y1 + g) – (y – y1) (x1 + g) = 0.

• The equation of the normal at P (x1, y1) of the circle x2 + y 2 = r2 is xy1 – yx1 = 0.

Chord of contact and Polar:

Chord of contact: –

to a circle S = 0 touch the circle at points A and B then the secant line AB is called the chord of contact of P with respect to S = 0

∗ If P (x1, y1) is an external point of the circle S ≡ x2 + y2 + 2gx + 2fy + c = 0, then the equation of the chord of contact of P with respect to S =0 is S1 = 0.

Note:

1. If the point P (x1, y1) is on the circle S = 0, then tangent itself can be defined as the chord of contact.
2. If the point P (x1, y1) s an interior point of the circle S = 0, then the chord of contact does not exist.

Pole and Polar: – Let S = 0 be a circle and P be any point if any line drawn through the point Pin the plane other than the centre of S = 0.then the points of intersection meets the circle in two points A and B, of tangents drawn at A and B lie on a line called polar of P and P, is called Pole of polar.

∗ The equation of the polar of P (x1, y1) with respect to the circle S = 0 is S1 = 0.

Note: –

1. If Plies outside the circle S = 0, then polar of P meets the circle in two points and the polar becomes the chord f contact of P.
2. If P lies on the circle S = 0, then the polar P becomes the tangent at P o the circle.
3. If P lies inside the circle S = 0, then the polar of P does not meet the circle.
4. If P is the centre of the circle S = 0, then the polar of P does not exist.
5. The pole of the line lx + my + n = 0 with respect to the circle x2 + y2 = r2 is
6. The pole of the line lx + my + n = 0 with respect to the circle x2 + y2 + 2gx + 2fy + c = 0 is
7. The polar of P (x1, y1) with respect to the circle S = 0 passes through Q (x2, y2)  ⟺ polar of Q passes through P.

Conjugate points: Two P and Q are said to be conjugate points with respect to the circle S = 0, if polar of P with respect to S = 0 passes through Q.

⇒ The condition for the points P (x1, y1), Q (x2, y2) to be conjugate with respect to the circle S = 0 is S12 = 0.

Conjugate lines: Two lines L1 = 0 and L2 = 0 are said to conjugate lines with respect to the circle S = 0 if the pole of L1 = 0 is lies on L2 = 0.

The condition for the lines l1x + m1y + n1 = 0 and l2x + m2y + n2 = 0 to be conjugate with respect to the circle S ≡ x2 + y2 + 2gx + 2fy + c = 0 is

r2 (l1l2 + m1m2) = (l1g + m1f – n1) (l2g + m2f – n2)

⟹ The condition for the lines l1x + m1y + n1 = 0 and l2x + m2y + n2 = 0 to be conjugate with respect to the circle S ≡ x2 + y2 = r2 is  r2 (l1l2 + m1m2) = n1n2

Inverse points: Let S = 0 be a circle with centre C and radius r. two points P and Q are said to be inverse points with respect to the circle S = 0 if

1. C, P, Q are collinear.
2. P, Q lies on the same side of C.
3. CQ = r2.

⟹  If lies inside of the circle S = 0, then Q lies outside of the circle.

⟹  If P lies on the circle S = 0, then P =Q.

⟹  Let S = 0 be a circle with centre C and radius r. The polar of P meets the line CP in Q iff  P, Q are inverse points.

⟹  f P, Q are inverse points with respect to S = 0, then P, Q are conjugate points with respect to the circle S = 0.

⟹  If P, Q are inverse points with respect to S = 0, then Q is the foot of the perpendicular from P on the polar of P with respect to the circle S = 0.

Equation of the chord with the given middle point:

The equation of the chord of the circle S = 0 having P (x1, y1) as its midpoint is S1 = S11.

Common tangents to the circle: ⟹ A straight line L = 0 is said to be common tangent to the circle S = 0 and S= 0 if it is a tangent to both S = 0 and S’ = 0.

Two circles are said to be touch each other if they have only one common tangent.

The relative position of two circles:

Let C1, C2 centres and r1, r2 be the radii of two circles S = 0 and S’ = 0respectively.

⟹2 direct common tangents and

2 transverse common tangents

Total 4 common tangents

⟹P divides C1C2 in the ratio r1: r2 internally

Here P is called the internal centre of similitude (I.C.S)

⟹ Q divides C1C2 in the ratio r1: r2 externally

Here Q is called the external centre of similitude (E.C.S)

⟹ Q divides C1C2 in the ratio r1: r2 externally

⟹ two direct common tangents and one common tangent. Total 3 tangents

Here Q is called the external centre of similitude (E.C.S)

3. Here Q is called the external centre of similitude (E.C.S)
⟹
Q divides C1C2 in the ratio r1: r2 externally

⟹ internal centre of similitude does not exist.

⟹ only one common tangent

internal centre of similitude does not exist.

no. of common tangents zero.

Note: the combined equation of the pair of tangents drawn from an external point P (x1, y1) to the circle S = 0 is S S11 = S12.

## 2.SYSTEM OF CIRCLES

A set of circles is said to be a system of circles if it contains at least two circles.

The angle between two intersecting circles: If two circles S = 0 and S’ = 0 intersect at P then the angle between the tangents of two circles at P is called angle between the circles at P.

⟹ If two circles S = 0 and S’ = 0 intersect at P and Q then the angle between the tangents of two circles at P and Q are equal.

⟹ If d is the distance between the centres of the two intersecting circles with radii r1, r2 and θ is the angle between the circles then. ⟹ If θ is the angle between the circles x2 + y2 + 2gx + 2fy + c = 0 and x2 + y2 + 2g’x + 2f’y + c’ = 0 then ⟹ Two intersecting lines are said to be Orthogonal if the angle between the circles is a right angle.

Condition for the orthogonality:

⟹ The condition that the two circles x2 + y2 + 2gx + 2fy + c = 0 and x2 + y2 + 2g’x + 2f’y + c’ = 0 cut each other orthogonally is 2gg’ + 2ff’ = c + c’.

⟹ If d is the distance between the centres of the two intersecting circles with radii r1, r2. Two circles cut orthogonally if d2 = r12 + r22.

∎  If S = 0, S’ = 0 are two circles intersecting at two distinct points, then S – S’ = 0 represents a common chord of these two circles.

∎ If S = 0, S’ = 0 are two circles touch each other, then S – S’ = 0 represents a common tangent of these two circles.

∎ If S ≡ x2 + y2 + 2gx + 2fy + c =  0 and L ≡ lx + my + n = 0 are the equation of the circle and  a line respectively intersecting each other, then S + λ L = 0 represent a circle passing through the point intersection of  S = 0 and L = 0 ∀ λ ∈ ℛ.

Radical axes: The radical axis of two circles s defined as the locus of the point which moves so that its powers with respect to the two circles are equal.

(OR)
The locus of a point, for which the powers with respect to given non-concentric circles are equal, is a straight line is called Radical axis of the given circles.

∎ The equation of Radical axis f the circles S = 0 and S’ = 0 is S – S’ = 0.

The radical axis of any two circles is perpendicular to the line joining their centres.

The lengths of tangents from a point on the radical axis of two circles are equal if exist.

Radical axis of two circles bisects all common tangents of the two circles.

∎ If the centres of any three circles are non-collinear then the radical axis of each pair of circles chosen from these three circles re concurrent. Radical centre:  The point of concurrence of radical axes of each pair of three circles is called radical centre (see above figure).

∎ If the circle S = 0 cuts the each of the two circle S’ = 0 and S’’ =0 orthogonally then the centre of S =0 lies on the radical axis of S’ = 0 and S’’ = 0.

∎ Radical axis of two circles is

• The ’common chord’ if the two circles intersect at two distinct points.
• The ‘common tangent’ at the point of contact if the two circles touch each other.

The radical axis of any two circles bisects the line joining the points of contact of common tangents to the circles.

Let S = 0, S’ = 0 and S’’ =0 be three circles whose centres are non- collinear and no two circles of these are intersecting then the circles having

• Radical centre of these circles as the centre of the circle.
• Length of the tangent from the radical centre to any one of these three circles cuts the given three circles orthogonally.

### CONIC SECTIONS    Conic: The locus of a point moving on a plane such that its distance from a fixed point and a fixed straight line is in the constant ratio is called Conic.

OR

The locus of a point moving on a plane such that its distance from a fixed point and a fixed line on the plane are in a constant ratio ‘e’, is called a Conic.

Focus: The fixed point is called focus and it is denoted by S.

Directrix: The fixed straight line is called the directrix.

Eccentricity: The constant ratio is called eccentricity and it is denoted by ‘e’.

Conic is the locus of a point P moving on a plane such that SP/PM = e, PM is the perpendicular distance from P to directrix at M.

If e = 1, then the conic is parabola.

if 0 < e < 1, then the conic is Ellipse.

if e > 1, then the conic is Hyperbola.

## 3.PARABOLA

• The standard form of parabola is y2 = 4ax.
• Focus S = (a. 0).
• Equation of directrix is x + a = 0.
• Vertex A = (0, 0) and A is the mid-point of SZ.

• Equation of the parabola with focus (α, β) and directrix lx + my + n = 0 is • If the focus is situated on the left side of the directrix, the equation of the parabola with vertex as the origin and the axis is X-axis is y2 = – 4ax.
• The vertex being the origin, if the axis of the parabola is taken as Y – axis, equation of the parabola is x2 = 4 ay or x2 = – 4 ay according to the focus is above or below the X-axis.

Nature of the curve:

The nature of the parabola f the equation y2 = 4 ax (a>0)

• F y = 0, then 4 ax = 0 and x = 0

∴ the curve passes through the origin.

∴ for any positive real value of x, we obtain two value of y of equal magnitude but opposite in sign. This shows that the curve is symmetric about X-axis and lies in the first and fourth quadrants.

The curve does not exist on the left side of the Y-axis since x ≥ 0 for any point (x, y) on the parabola.

Chord: The line segment joining two points on a parabola is called a chord.

Focal chord: A chord which is passing through focus is called Focal Chord.

Double ordinate: A chord through a point P on the parabola, which is perpendicular to the axis of the parabola is called Double ordinate.

Latus rectum: The double ordinate passing through the focus is called Latus rectum.

⟹ Length of Latus rectum = 4a.

Various forms of the parabola

focus: (a, 0)

equation of directrix: x + a = 0

axis of parabola: y = 0

vertex: (0. 0)

equation of directrix: x − a = 0

focus: (−a, 0)

axis of parabola: y = 0

vertex: (0. 0)

focus: (0, a)

equation of directrix: y + a = 0

axis of parabola: x = 0

vertex: (0. 0)

focus: (0, −a)

equation of directrix: y − a = 0

vertex:  (0. 0)    axis of parabola: x = 0

focus: (h + a, k)

equation of directrix: x – h + a = 0

axis of parabola: y – k = 0

vertex: (h. k)

focus: (h – a, k)
equation of directrix: x – h – a = 0

axis of parabola: y – k = 0

vertex: (h. k)

focus: (h, k + a)

equation of directrix: y – k + a = 0

axis of parabola: x – h = 0

vertex: (h. k)

focus: (h, k – a)

equation of directrix: y – k – a = 0

vertex: (h. k)
axis of parabola: x – h =0

focus: (α, β)

equation of directrix: lx + my + n = 0

axis of parabola: m (x – α) – l (y – β) = 0

vertex: A

Note:

1. Equation of the parabola whose axis parallel to X – axis is x = ly2 + my + n.
2. Equation of the parabola whose axis parallel to Y – axis is y = lx2 + mx + n.

Focal distance:  The distance of a point on the parabola from its focus is called Focal distance.

⟹ Focal distance of parabola s x1 + a

Parametric equations of a parabola:

The point (at2, 2at) satisfy the equation y2 = 4ax, the parametric equations of parabola are  x = at2, y = 2at. The point P(at2, 2at) is generally denoted by the point ‘t’ or P(t).

Notation:

1. S ≡ y2 – 4 ax
2. S1 ≡yy1 – 2a (x + x1)
3. S12 ≡ y1y2 – 2a (x1 + x2)
4. S11 ≡ y12 – 4 ax1

Equation of a tangent and normal at a point on the parabola:

∎ y = mx + c is a tangent to the parabola y2 = 4ax, then c = a/m or a =cm, and the point of contact is (a/m2, 2a/m).

∎ if m = 0, the line y = c is parallel to the axis of the parabola (i.e., x – axis)

y = c ⟹ c2 = 4ax ⟹ x = c2 /4a

∴ point of contact is (c2/4a, c).

∎ if m ≠ 0 and c = 0, then

Y = mx ⟹ x = 4a/m2 and y = 4a/m

∴ point of contact is (4a/m2, 4a/m).

∎ The equation of the chord joining the points (x1, y1) and (x2, y2) is S1 + S2 = S12.

∎ The equation of the tangent at P (x1, y1) to the parabola S = 0 is S1= 0.

∎ The equation of the normal at P (x1, y1) is (y – y1) = – y1/2a (x – x1).

Parametric form:

∎ The equation of the tangent at a point ‘t’ on the parabola y2 = 4ax is x – yt + at2 = 0.

∎ Equation of the normal at a point ‘t’ on the parabola y2 = 4ax is y + xt = 2at + at3.

∎ The condition for the straight-line lx + my + n = 0 to be a tangent to the parabola y2 = 4 ax is

am2 = nl and point of contact is (n/l, –2 am/l).

∎ common tangent to the parabolas y2 = 4 ax and x2 = 4 by is x a1/3 + y b1/3 + a2/3 b2/3 = 0.

∎ The equation of the chord of contact of the external point (x1, y1) w.r. t parabola S = 0 is S1 = 0.

∎ The equation of the polar of the point (x1, y1) w.r. t parabola S = 0 is S1 = 0.

∎ The pole of the line lx + my + n = 0 w.r.t. parabola y2 = 4ax is (n/l, -2am/l).

∎ If two points P (x1, y1), Q (x2, y2) are conjugate points w.r.t. parabola S = 0, then S12 = 0.

∎ The lines l1x + m1y + n1 = 0 and l2x + m2y + n2 = 0 are conjugate lines with respect to the parabola y2 = 4 ax, then l1n2 + l2n1 = 2a m1m2.

## 4.ELLIPSE

⇒b2 = a2 (1 – e2) ⇒ e2 – 1 = -b2/a2 Major and Minor axis:

⟹ The line segment AA’ and BB’ of length 2a and 2b respectively are axes of the Ellipse.

⟹ If a > b AA’ is called Major axis and BB’ is called Minor axis and vice-versa if a<b.

Various form of Ellipse:

Major axis: along the x-axis

Length of Major axis:2a

Minor axis: along y – axis

Length of Minor Axis:2b

Centre: (0, 0)

Foci: S = (ae, 0) and S’ = (–ae, 0)

Equation of directrices: x = a/e and x = –a/e

Major axis: along y – axis

Length of Major axis:2b

Minor axis: along x – axis

Length of Minor Axis:2a

Centre: (0, 0)

Foci: S = (0, be) and S’ = (0, –be)

Equation of directrices: x = b/e and x = –b/e

Centre not at the origin

Major axis: along with y = k

Length of Major axis:2a

Minor axis: along x = h

Length of Minor Axis:2b

Centre: (h, k)

Foci: S = (h +ae, k) and S’ = (h – ae, k)

Equation of directrices: x = h + a/e and x = h – a/e

Major axis: along x = h

Length of Major axis:2b

Minor axis: along with y = k

Length of Minor Axis:2a

Centre: (h, k)

Foci: S = (h, k + be) and S’ = (h, k – be)

Equation of directrices: xy = k + b/e and y = k – b/e

Chord: The line segment joining two points on a parabola is called a  chord of Ellipse.

Focal chord: A chord which is passing through one of the foci is called Focal Chord.

Latus rectum: A focal chord perpendicular to the major axis of the Ellipse is called Latus Rectum. Ellipse has two latera recta.

Length of the Latus rectum:

L = (ae, b2/a), L’ = (ae, -b2/a) and L1 = (-ae, b2/a), L1’= (-ae, -b2/a).

length of the Latus rectum = 2b2/a.

L = (a2/b, be), L’ = (-a2/b, be) and L1 = (a2/b, -be), L1’ = (-a2/b, -be).

Auxiliary circle: The circle described on the major axis of an Ellipse as the diameter is called the Auxiliary circle of the Ellipse. The Auxiliary circle of the Ellipse is x2 + y2 = a2.

Notation:

Equation of Tangent and Normal

∎ The point of contact of two parallel tangents to the Ellipse are (-a2m/c, b2/c) and (a2m/c, -b2/c)

∎ The equation of the chord joining two points (x1, y1) and (x2, y2) on the Ellipse S = 0 is S1 + S2 = S12.

∎ When θ = 0, π; equation of Normal is y =0.

∎ When θ = π/2, 3π/2; equation of Normal is x =0.

∎ The condition for the line lx + my + n = 0 to be a tangent the Ellipse S = 0 is a2l2 + b2m2 = n2.

∎ The condition for the line x cosα + y sinα = p to be a tangent the Ellipse S = 0 is a2 cos2 α + b2 sin2 α = p2.

∎ The pole of the line lx + my + n = 0 with respect to the Ellipse S = 0 is (-a2l/n, -b2m/n).

∎ The condition for the two lines l1x + m1y + n1 = 0 and l2x + m2y + n2 = 0 to be conjugate with respect to the Ellipse S = 0 is a2l1l2 + b2m1m2 = n1n2. a2l1l2.

## 5.HYPERBOLA

Centre: C (0, 0)

Foci: (± ae, 0)

Directrix: x = ± a/e.

Rectangular Hyperbola:

If in a Hyperbola the length of the transverse axis (2a) is equal to the length of the conjugate axis(2b), then the hyperbola is called rectangular hyperbola.

Auxiliary circle: The circle described on the transverse axis of hyperbola as diameter is called the auxiliary circle of the hyperbola.

The equation of the auxiliary circle of S = 0 is x2 + y2 = a2.

Parametric equations:  The parametric equations of the Parabola S = 0 are x = a secθ and y = b tanθ.

Conjugate Hyperbola:

The hyperbola whose transverse and conjugate axis are respectively the conjugate and transverse axis of a given hyperbola is called a conjugate hyperbola.

The equation of hyperbola conjugate to   S ≡  is S’ ≡

The transverse axis lies on along X-axis and its length is 2a.

The transverse axis lies on along Y-axis and its length is 2b.

The conjugate axis lies on along X-axis and its length is 2a.

Various form of Hyperbola: The transverse axis along X-axis: y =0

Length of the transverse axis:2a

The conjugate axis along Y-axis: x = 0

Length of the conjugate axis: 2b

Centre: (0, 0)

Foci: (± ae, 0)

Equation of the directrices: x = ± a/e

The transverse axis along Y-axis: x = 0

Length of the transverse axis:2b

The conjugate axis along X-axis: y = 0

Length of the conjugate axis: 2a

Centre: (0, 0)

Foci: (0, ± be)

Equation of the directrices: y = ± b/e

Centre not at the origin:

The transverse axis along X-axis: y = k

Length of the transverse axis:2a

The conjugate axis along Y-axis: x = h

Length of the conjugate axis:2b

Centre: (h, k)

Foci: (h± ae, k)

Equation of the directrices: x = h± a/e

The transverse axis along Y-axis: x = h

Length of the transverse axis:2b

The conjugate axis along X-axis: y = k

Length of the conjugate axis: 2a

Centre: (h, k)

Foci: (h, k ± be)

Equation of the directrices: y = k± b/e

Equation of tangent and normal at a point on the Hyperbola:

∎ The equation of the tangent at P (x1, y1) to the hyperbola S = 0 is S1 = 0.

∎ The condition for a straight-line y = mx + c to be a tangent to the hyperbola S = 0 is c2 = am2 − b2.

Asymptotes of a hyperbola:

## 6. INTEGRATION

∎ Let E be a subset of R such that E contains a right or left the neighbourhood of each of its points and let f: E → R be a function. If there is a function F on E such that F’(x) = f(x) ∀ x ∈ E, then we call F an anti-derivative of f or a primitive of f.

Indefinite integral: Let f: I→R. Suppose that f has an antiderivative F on I. Then we say that f has an integral on I and for any real constant c, we call F + c an indefinite integral of over I, denote it by    ∫f(x) dx and read it as ‘integral’ f(x) dx.

∫f = ∫f(x) dx = F(x) + c. here c is called constant of integration.

In the indefinite integral ∫f(x)dx, f is called ‘integrand’ and x is called the variable of integration.

⟹ if f: I⟶R is differentiable on I, then ∫f’(x)dx = f(x) + c.

Standard forms: Properties of integrals:

∎ ∫ (f ±g) (x) dx = ∫f(x) dx ± ∫g(x) dx + c

∎ ∫(af) (x) dx = a ∫f(x) dx + c

∎ ∫ (f1 + f2 + … + fn) (x) dx = ∫f1(x) dx + ∫f2(x) dx + … +∫fn(x) dx +c

∎ ∫f(g(x)) g’(x) dx = F(g(x)) + c

∎ ∫f(ax + b) dx = 1/a F(ax +b) + c

Some important formulae:

1. ∫eax dx = 1/a eax + c
2. ∫sin (ax + b) dx = -1/a cos (ax + b) + c
3. ∫cos (ax + b) dx = 1/a sin (ax + b) + c
4. ∫sec2 (ax + b) dx = 1/a tan (ax + b) + c
5. ∫ cossec2 (ax + b) dx = 1/a cot (ax + b) + c
6. ∫cosec (ax + b) cot (ax + b) dx = -1/a cosec (ax + b) + c
7. ∫sec (ax + b) tan (ax + b) dx = 1/a sec (ax + b) + c  Integration by parts:

Let u, v real valued differentiable functions in I. Suppose that u’v has an integral on I, then uv’ has an integral on I and

∫(uv’) (x) dx = (uv) – ∫(u’v) (x) dx + c or ∫(uv) dx = u ∫v dx – ∫ [u’ ∫v dx] dx + c

Integration of exponential functions:

∫ex dx = ex + c; ∫x ex dx = (x – 1) ex + c

∫ ex [f(x) +f’(x)] dx = ex f(x) + c

Integration of logarithmic functions:

∫log x dx = x log x – x + c

Integration of inverse trigonometric functions: Working rule:  reduce ax2 + bx + c to the form of a[(x + α)2 + β] and then integrate using the substitution t = x + α.

Working rule:

Case(i) if a >0 and b2 – 4ac < 0, then reduce ax2 + bx + c to the form of a[(x + α)2 + β] and then integrate.

Case(ii) if a <0 and b2 – 4ac >0, then reduce ax2 + bx + c to the form of (-a) [ β – (x + α)2 +] and then integrate.

Evaluation of integrals form Working rule:  write px + q in the form of A (ax2 + bx +c)’ + B, then integrate.

Evaluation of integrals form Working rule:  write cos x =cos2(x/2) – sin2(x/2) and sin x = 2 sin(x/2) cos (x/2)

Put t = tan(x/2), then dt = ½ sec2 (x/2) dx

Cos x = 1 – t2 / 1 + t2, sin x = 2t/1 + t2 then integrate.