Question

13. 1 + cos2 2x = 2 (cos4 x + sin 4
4x)​

Answer 1

$\huge\mathbb{\purple{ASHxPIKACHU}}$

Answer 2

Solution:

R.H.S

= 2( Cos^4x + sin^4x)

=2{( Cos^2x +sun ^2 x) - 2sin^2 x cos^2x

=2 - 4sin^2x cos^2x

=2 - 4. 1- Cos ^2x × 1+Cos ^2 2x

________. _________

2 2

= 2-( 1-Cos ^2 2x )

= 1+ Cos ^2 2x = 2

Hence Proved.

Thank you....