NCERT Solutions For Class 11 Maths chapter-3 Trigonometric Functions Miscellaneous Exercise

NCERT Solutions For Class 11 Maths chapter-3 Trigonometric Functions Miscellaneous Exercise

NCERT Solutions For Class-11 Maths Chapter 3 Trignometric Functions Miscellaneous Exercise prepared by the expert of Physics Wallah score more with Physics Wallah NCERT Class-11 maths solutions. You can download solution of all chapters from Physics Wallah NCERT solutions of class 11.

NCERT Solutions for Class-11 Maths Miscellaneous Exercise

Prove that:

Question 1. Prove that: 2cos π/13 cos 9π/13 + cos 3π/13 + cos 5π/13 = 0

Solution :

0 = R.H.S.

Question 2. Prove that: (sin 3x + sin x) sin x + (cos 3x – cos x) cos x = 0

Solution :
L.H.S. = (sin 3x + sin x) sin x + (cos 3x – cos x) cos x

Question 3. Prove that: (cosx + cosy) ² + (sinx − siny) ² = 4cos ² x /2 + y/2

Solution :
L.H.S. = (cosx + cosy) ² + (sinx − siny) ²

Question 4. (cosx − cosy) ² + (sinx − siny) ² = 4sin ² x/2 − y/2

Solution :
L.H.S. = (cosx − cosy) ² + (sinx − siny) ²

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

Solution :
L.H.S. = sinx + sin3x + sin5x + sin7x = (sinx + sin5x) + (sin3x + sin7x)

Question 6.

Solution :

Question 7. Prove that: sin 3x + sin 2x − sin x = 4sin x cos x/2 cos3 x/2

Solution :

Question 8 Find sin x/2,cos x/2 and tan x/2 in each of the following:

tan′x =−4/3,x in quadrant II.

Solution :
:

Question 9. cosx=−1/3,x in quadrant III.

Solution :

Question 10. sinx=1/4,xin quadrant II.

Solution :