Question

Rewrite with only sin x and cos x.

sin 3x - cos x
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a. 2 sin x - sin3x - cos x

b. 2 sin x cos2x + sin x - 2 sin3x - cos x

c. 2 sin3x cos4x + 1

d. 3 sin x cos x - sin3x - cos x

Answer 1

is that sin^3 or is that sin(3x)

Answer 2

sin(3x)

Answer 3

so you can use the identity

sin(A+B) = sin(A)cos(B) + cos(A)sin(B)

Answer 4

sin(3x) = sin(x+2x)

sin(3x) = sin(x)cos(2x) + cos(x)sin(2x)

sin(3x) = sin(x)cos(2x) + cos(x)(2*sin(x)*cos(x)) ... use identity sin(2A) = 2sin(A)cos(A)

keep going

Answer 5

im a bit stuck

Answer 6

when i did sin(A+B) = sin(A)cos(B) + cos(A)sin(B), my result was 0

Answer 7

\[\sin 3x=\sin \left( 2x+x \right)=you can solve\]
again sin 2x =2 sin x cos x
\[\cos 2x=\cos ^{2}x -\sin ^{2}x\]