Question

Verify the identity.

sin (4u) = 2 sin (2u) cos (2u)

Please help, verifying these kind of equations is tricky for me.

Answer 1

Hmm. you can try doing it like this:

sin(2u + 2u) = sin(2u) * cos(2u) + cos(2u) * sin(2u) = 2sin(2u)*cos(2u)

Note: I referred to: sin(A + B) = sinAcosB + cosAsinB

Answer 2

Oh, I see. Is that the final answer?

Answer 3

I mean, is that it? Usually these questions take up more space.
>_<

Answer 4

I'm pretty sure it is, yes

Answer 5

you can also use the identity that

\[\bf \large \boxed{\sin 2A= 2\sin A \times \cos A }\]

Answer 6

treating \[4u=2 \times (2u) \]