A. cos 7θ-7cos 5θ+21cos 3θ+35cos θ
B. cos 7θ-7cos 5θ-21cos 3θ-35cos θ
C. cos 7θ-7cos 5θ+21cos 3θ-35cos θ
D. cos 7θ+7cos 5θ+21cos 3θ+35cos θ
8sin4θ=
32cos4 θ.sin2 θ=
27 cos8 θ=
128 sin8 θ=
27 cos5 θsin3 θ=
The last terms in the expantions of sin 8θ, sin 9θ respectively are
If cos α+ cos β=0= sin α + sin β then cos(α - β)=
If 16 sin5 θ=asin 5 θ+b sin 3θ+c sin θ then
64cos3 θsin4 θ=