Prove that cos 4 a minus cos 2a is equal to sin for a minus sin 2a
Answers
Answered by
7
Answer:
cos 4 A - Cos2A
= (cos2A)2 - (cosA)2
= (1- sin2A)2 - cos2A
= 1 + sin4A - 2sin2A -( 1- sin2A)
=1+ sin4A - 2 sin2A -1 + sin2A
=sin4A - sin2A
Similar questions