Question

3(cos^2 (30)-cos^2 (60))=8(cos^2(30)*cos^2(60)) prove

Answer 1

Answer:

We know,

cos2A = 2cos^2(A) -1

=> cos^2(A)=(1+cos2A)/2 ,putting A=30°

=> cos^2(30°) = (1+ cos2*30°)/2

=> (1+cos60°)/2 =(1+1/2)/2 =(3/2)/2 = 3/4

Cos^2(30°) = 3/4