Question

Question #79582

Answer 1

This is just a trig question to get the solution into a different form;

Recall the sine addition formula:

`sin (A+ B) =sinAcosB + cosAsinB`

Put `A=B` to get a double angle formula;

`sin (A+ A) =sinAcosA + cosAsinA`
`:. sin (2A) =2sinAcosA`

If we put `A=2x` then;
`:. sin (2(2x)) =2sin2xcos2x`
`:. sin 4x =2sin2xcos2x`

Hence, `sin2xcos2x = 1/2sin 4x`