Question

$\huge \mathfrak\orange{hello}$


Help me in the above attachment..

Answer 1

$<marquee>☺☺Hi there☺☺</marquee>$

L.H.S.= cos 6x

=cos 3(2x)

=4 cos32x– 3 cos2x

=4 [2 cos2x –1)3– 3 (2 cos2x– 1)

=4 [(2 cos2x)3– (1)3– 3 (2 cos2x)2+ 3 (2 cos2x)]– 6cos2x+ 3

=4 [8cos6x– 1 – 12 cos4x+ 6 cos2x]– 6 cos2x+ 3

=32 cos6x– 4 – 48 cos4x+ 24 cos2x– 6 cos2x+ 3

=32 cos6x–48 cos4x+ 18 cos2x– 1

=R.H.S.

Thanks ♥♥

Answer 2

L.H.S.= cos 6x

=cos 3(2x)

=4 cos32x– 3 cos2x

=4 [2 cos2x –1)3– 3 (2 cos2x– 1)

=4 [(2 cos2x)3– (1)3– 3 (2 cos2x)2+ 3 (2 cos2x)]– 6cos2x+ 3

=4 [8cos6x– 1 – 12 cos4x+ 6 cos2x]– 6 cos2x+ 3

=32 cos6x– 4 – 48 cos4x+ 24 cos2x– 6 cos2x+ 3

=32 cos6x–48 cos4x+ 18 cos2x– 1

=R.H.S.

Thanks ♥♥