NCERT Solutions
Class 11 Maths
Trigonometric Functions
Electric charges

Ex.3.1 Q.1

Find the radian measures corresponding to the following degree measures:

(1) 25°                           

(2) – 47° 30'                          

(3) 240°                     

(4) 520°

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Ex.3.1 Q.2

Find the degree measures corresponding to the following radian measures. (Use π = 227 )      

(1)                               

(2) -4                                

(3)                                

(4)

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Ex.3.1 Q.3

A wheel makes 360 revolutions in one minute. Through how many radians does it turn in one second?

 

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Ex.3.1 Q.4

Find the degree measure of the angle subtended at the centre of a circle of

radius 100 cm by an arc of length 22 cm. (Use π = )

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Ex.3.1 Q.5

In a circle of diameter 40 cm, the length of a chord is 20 cm. Find the length of minor arc of the chord.

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Ex.3.1 Q.6

If in two circles, arcs of the same length subtend angles 60° and 75° at the centre, find the ratio of their radii.

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Ex.3.1 Q.7

Find the angle in radian though which a pendulum swings if its length is 75 cm and the tip describes an arc of length                                                                                                                        

(1) 10 cm                                           

(2) 15 cm                                     

(3) 21 cm

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Ex.3.2 Q.1

Find the values of other five trigonometric functions if cos x = - , x lies in third quadrant.

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Ex.3.2 Q.2

Find the values of other five trigonometric functions if sin x = , x lies in second quadrant.

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Ex.3.2 Q.3

Find the values of other five trigonometric functions if cot x = , x lies in third quadrant.

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Ex.3.2 Q.4

Find the values of other five trigonometric functions if sec x = , x lies in fourth quadrant.

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Ex.3.2 Q.5

Find the values of other five trigonometric functions if tan x = - , x lies in second quadrant.

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Ex.3.2 Q.6

Find the value of the trigonometric function sin 765°.

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Ex.3.2 Q.7

Find the value of the trigonometric function cosec (–1410°)

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Ex.3.2 Q.8

Find the value of the trigonometric function tan  .

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Ex.3.1 Q.9

Find the value of the trigonometric function sin (- ).

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Ex.3.2 Q.10

Find the value of the trigonometric function cot (- ).

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Ex.3.3 Q.1

sin2  + cos2  - tan2  = -

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Ex.3.3 Q.2

2sin2  + cosec2  × cos2  =

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Ex.3.3 Q.3

Prove that: cot2  + cosec  + 3 tan2  = 6

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Ex.3.3 Q.4

Prove that: 2sin2  + 2cos2  + 2sec2  = 6

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Ex.3.3 Q.5

Find the value of:

(1) sin 75°                                                 

(2) tan 15°

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Ex.3.3 Q.6

Prove that: cos (  - x) × cos (  - y) - sin (  - x) × sin (  - y) = sin (x + y)

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Ex.3.3 Q.7

Prove that: tan (  + x) ÷ tan (  - x) = {(1 + tan x) ÷ (1 + tan x)}2

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Ex.3.3 Q.9

cos (  + x) cos (2π + x) [cot (  - x) + cot (2π + x)] = 1

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Ex.3.3 Q.10

Prove that sin (n + 1) x sin (n + 2) x + cos (n + 1) x cos (n + 2) x = cos x

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Ex.3.3 Q.11

Prove that: cos (  + x) - cos (  - x) = -√2sin x

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Ex.3.3 Q.12

Prove that sin2 6x – sin2 4x = sin 2x sin 10x

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Ex.3.3 Q.13

Prove that cos2 2x – cos2 6x = sin 4x sin 8x

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Ex.3.3 Q.14

Prove that sin 2x + 2sin 4x + sin 6x = 4cos2 x sin 4x

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Ex.3.3 Q.15

Prove that cot 4x (sin 5x + sin 3x) = cot x (sin 5x – sin 3x)

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Ex.3.3 Q.16

Prove that: (cos 9x – cos 5x) ÷ (sin 17x – sin 3x) = -sin 2x ÷ cos 10x

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Ex.3.3 Q.17

Prove that: (sin 5x + sin 3x) ÷ (cos 5x + cos 3x) = tan 4x

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Ex.3.3 Q.18

Prove that: (sin x – sin y) ÷ (cos x + cos y) = tan (x - y) ÷ 2

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Ex.3.3 Q.19

Prove that: (sin x + sin 3x) ÷ (cos x + cos 3x) = tan 2x

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Ex.3.3 Q.20

Prove that: (sin x – sin 3x) ÷ (sin2 x – cos2 x) = 2 sin x

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Ex.3.3 Q.21

Prove that: (cos 4x + cos 3x + cos 2x) ÷ (sin 4x + sin 3x + sin 2x) = cot 3x

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Ex.3.3 Q.22

Prove that: cot x cot 2x – cot 2x cot 3x – cot 3x cot x = 1

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Ex.3.3 Q.23

Prove that: tan 4x = {4 tan x (1 – tan2 x)} ÷ (1 – 6tan2 x + tan4 x)

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Ex.3.3 Q.24

Prove that: cos 4x = 1 – 8sin2 x cos2 x

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Ex.3.3 Q.25

Prove that: cos 6x = 32 cos6 x – 48 cos4 x + 18 cos2 x – 1

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Ex.3.4 Q.1

Find the principal and general solutions of the equation tan x = √3

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Ex.3.4 Q.2

Find the principal and general solutions of the equation sec x = 2

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Ex.3.4 Q.3

Find the principal and general solutions of the equation cot x = -√3

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Ex.3.4 Q.4

Find the general solution of cosec x = –2

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Ex.3.4 Q.5

Find the general solution of the equation cos 4x = cos 2x

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Ex.3.4 Q.6

Find the general solution of the equation cos 3x + cos x – cos 2x = 0

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Ex.3.4 Q.7

Find the general solution of the equation sin 2x + cos x = 0

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Ex.3.4 Q.8

Find the general solution of the equation sec2 2x = 1 – tan 2x

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Ex.3.4 Q.9

Find the general solution of the equation sin x + sin 3x + sin 5x = 0

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Ex.Misc.Q.1

Prove that: 2cos  cos  + cos  cos  = 0

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Ex.Misc.Q.2

Prove that: (sin 3x + sin x) sin x + (cos 3x – cos x) cos x = 0

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Ex.Misc.Q.3

Prove that: (cos x + cos y)2 + (sin x – sin y)2 = 4 cos2 (x + y) ÷ 2

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Ex.Misc.Q.4

Prove that: (cos x - cos y)2 + (sin x – sin y)2 = 4 sin2 (x - y) ÷ 2

 

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Ex.Misc.Q.5

Prove that: sin x + sin 3x + sin 5x + sin 7x = 4 × cos x × cos 2x × sin 4x

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Ex.Misc.Q.6

Prove that: {(sin 7x + sin 5x) + (sin 9x + sin 3x)} ÷ {(cos 7x + cos 5x) + (cos 9x + cos 3x)} = tan 6x

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Ex.Misc.Q.7

Prove that: sin 3x + sin 2x – sin x = 4 × sin x × cos ( ) × cos ( )

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Ex.Misc.Q.8

Find sin , cos  and tan , if tan x = − , x in quadrant II

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Ex.Misc.Q.9

Find sin , cos  and tan  for cos x = − , x in quadrant II.

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Ex.Misc Q.10

Find sin , cos  and tan  for sin x = , x in quadrant II

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Complete NCERT Solutions: Classes 6 to 12, All Chapters

NCERT Solution for class 6
NCERT Solution for class 7
NCERT Solution for class 8
NCERT Solution for class 9
NCERT Solution for class 10
NCERT Solution for class 11
NCERT Solution for class 12

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