Rewrite using only sine and cosine:
sin 3x
I know the double angle formula and how to use it, could someone walk me through it though so I understand it completely?

Question

Rewrite using only sine and cosine:
sin 3x
I know the double angle formula and how to use it, could someone walk me through it though so I understand it completely?

anonymous · Answer

$$\sin(3x)= \sin (2x + x)$$

remember that 

$$\sin (A +B) = sinAcosB + sinBcosA$$

anonymous · Answer

So in this case $$\sin(3x) = \sin(2x)\cos(x) + \sin(x)\cos(2x)$$

which is $$2\sin(x)\cos ^{2}x + \sin(x)(1-2\sin^{2}(x))$$

anonymous · Answer

do you follow how I used the sin2x = 2sinxcosx and the cos2x = 1- 2sin^2(x) ?

anonymous · Answer

So you broke sin(3x) to create two double angle formulas of sin(2x) and cos(2x)?

anonymous · Answer

yw

anonymous · Answer

I broke it into one double angle formula ... the other one was just a result of breaking the ladder...