Question

Verify the equation; Trigonometric problem

Answer 1

sin 4u = 2sin 2u cos 2u

Answer 2

@Jhannybean If I'm remembering correctly you're pretty good at this, could you start me off, please?

Answer 3

sin(u+v) = sin(u)cos(v)+cos(u)sin(v). take u = 2*theta and v = 2*theta. (your "u" is my "theta") can you solve it now?

Answer 4

Maybe, could I cross multiple cos/sin + sin/cos..?

Answer 5

@Luigi0210 I'm sorry to keep bothering you but I'm not sure what to do

Answer 6

\[\large \sin \color{blue}{(2x)}= \color{blue}2\sin \color{blue}{(x)}\cos \color{blue}{(x)}\] so sin 4x is just double that amount, right?
\[\sin \color{blue}{(4x)}= \sin \color{blue}{(2*2x)}=\color{blue}2\sin \color{blue}{(2x)}\cos \color{blue}{(2x)}\]