Question

8Sin^2 A/4. Cos^2 A/4 = 1-CosA

Answer 1

Answer:

Use two formulas

sin(2A) = 2sinAcosA

cos(2A) = 1 - 2sin^2(A)

So, sin (A/2)= 2 sin(A/4) cos(A/4)

And, cosA = 1 - 2sin^2(A/2)

we can write also,

2sin^2(A/2) = 1 - cosA

ques. is

8sin^2(A/4)cos^2(A/4)

=2 * 2 sin(A/4) cos(A/4) * 2 sin(A/4) cos(A/4)

=2 * sin(A/2) * sin(A/2)

=2sin^2(A/2)

=1 - cosA

Explanation:

Hope it helps :-)