Question

How do you write sin3x in terms of sinx??___......fast​

Answer 1

Sin3x= Sin(2x+x) = Sin2xCosx+Cos2xSinx = 2SinxCosxCosx + (Cos^2x - Sin^2x) Sinx = 2SinxCos^2x + Cos^2xSinx - Sin^3x

= 3Sinx Cos^2x - Sin^3x

= 3Sinx(1 - Sin^2x) - Sin^3x

= 3Sinx - 3Sin^3x - Sin^3x

= 3Sinx - 4Sin^3x

Answer 2

Sin3x= Sin(2x+x) = Sin2xCosx+Cos2xSinx = 2SinxCosxCosx + (Cos^2x - Sin^2x) Sinx = 2SinxCos^2x + Cos^2xSinx - Sin^3x

= 3Sinx Cos^2x - Sin^3x

= 3Sinx(1 - Sin^2x) - Sin^3x

= 3Sinx - 3Sin^3x - Sin^3x

= 3Sinx - 4Sin^3x