# Equivalent expression for sinx^3

## Homework Statement

Find an equivalent expression for sin3x in terms of function values of x, 2x, 3x, raised only to the first power.

## The Attempt at a Solution

stuck! dont know where to begin I am reviewing for my exam right now I remember doing one of these problems before but I cant remember how.

sinx(sinx2)

sinx[(1-cos2x)/2]

am i on the right track?

tiny-tim
Homework Helper
Find an equivalent expression for sin3x in terms of function values of x, 2x, 3x, raised only to the first power.

stuck! dont know where to begin I am reviewing for my exam right now I remember doing one of these problems before but I cant remember how.

sinx(sinx2)

sinx[(1-cos2x)/2]

am i on the right track?

Hi synergix! (btw, don't write (sinx2), write either (sinx)2 or sin2x)

Your equation is correct, but I don't think it's what they're asking for …

it has a (sinx)(cos2x) … if you're allowed that, you might as well have (sinx)(sinx)(sinx).

I think they want a sum of first powers, each on its own.

Hint: start at the end …

what is sin(3x) in terms of powers of sinx? 