- #1
Slicktacker
- 9
- 0
Hi all, I have a question proving an identity:
[tex]sin(4x) = 4sin(x)cos^3(x)-4sin^3(x)cos(x)[/tex]
I can't seem to figure it out. I know I should be using the known identities:
[tex]sin(2x) = 2sin(x)cos(x)[/tex]
and probably:
[tex]cos(2x) = 1-2sin^2(x)[/tex]
but I'm stuck. Please help!
Thanks!
[tex]sin(4x) = 4sin(x)cos^3(x)-4sin^3(x)cos(x)[/tex]
I can't seem to figure it out. I know I should be using the known identities:
[tex]sin(2x) = 2sin(x)cos(x)[/tex]
and probably:
[tex]cos(2x) = 1-2sin^2(x)[/tex]
but I'm stuck. Please help!
Thanks!