Q5 of 268 Page 4

Prove the following :
When α =60°

Solving, L.H.S.

= [(a)² – (b)² = (a+b)(a-b)]

We know that

Putting the values, we get

= 3 = R.H.S.

Evaluate the following :

Prove the following :

When B = 30°

Prove the following :

cos(A – B) = cos A. cos B + sinA . sin B if A=B=60^o

Prove the following :

4(sin⁴30° + cos⁴ 60°) – 3(cos² 45° – sin²90°) = 2