Home
Class 11
MATHS
If sinbeta is geometric mean between sin...

If `sinbeta` is geometric mean between `sin alpha and cos alpha , ` then `cos 2beta` =

A

`2 sin^(2) ((pi)/(4) - alpha) or 2 cos^(2) ((pi)/(4) + alpha)`

B

`2 sin^(2) ((pi)/(3)-alpha) or 2 cos^(2) ((pi)/(3)+alpha)`

C

`sin^(2) ((pi)/(4)-alpha)or cos^(2) ((pi)/(4) + alpha)`

D

`sin^(2) ((pi)/(3)-alpha)or cos^(2) ((pi)/(3) + alpha)`

Text Solution

Verified by Experts

The correct Answer is:
A
Promotional Banner

Similar Questions

Explore conceptually related problems

Let cos beta is the geometric mean between sin alpha and cos alpha , where 0 lt alpha lt beta lt pi//2 , then cos 2beta is equal to

If sin beta is the G.M between sin alpha and cos alpha then (cos alpha - sin alpha)^(2) - 2 cos^(2) beta =

If sin alpha = sin beta and cos alpha = cos beta then

If cos alpha + cos beta = a, sin alpha + sin beta = b and theta is the arithmetic mean between alpha and beta then sin 2 theta + cos 2 theta is equal to

sin alpha=sinbeta, cos alpha=cos beta then

If cos alpha + cos beta = 3/2 and sin alpha + sin beta = 1/2 and theta is the arithmetic mean of alpha and beta then sin 2 theta + cos 2 theta

2 sin^(2) beta + 4 cos( alpha+ beta) sin alpha sin beta + cos ( 2 alpha + 2 beta )=

If alpha, beta are complementary angles, sin alpha = (3)/(5) then cos alpha cos beta-sin alpha sin beta =

If alpha , beta are complementary angles , sin alpha = 3//5 , then sin alpha cos beta - cos alpha sin beta =