Simplify:sinα(1+cosα)+(1+cosα)sinα
If tanθ = sinα−cosαsinα+cosα, then sinα+cosα and
sinα−cosα must be equal to
Prove that cosα+cos(α+β)+cos(α+2β)+.....+cos(α+(n−1)β)
=cos{α+n−12β}sin(nβ2)sinβ2 for all n ϵ N.