Question

Write the expression as the sine, cosine, or tangent of an angle.

sin 8x cos x - cos 8x sin x

Answer 1

@iPwnBunnies

Answer 2

@LieutenantGeneral

Answer 3

\(\Large \sin A \cos B - \cos A \sin B = \sin(A-B)\)

Answer 4

A = 8x
B =x

Answer 5

Sin (x+y) = sin(x)cos(y) + sin(y)cos(x)

x = 8x
y = 2x

Sin (8x + 2x) = sin(10x)
sin 8x cos 2x + cos 8x sin 2x
= sin (8x + 2x)
= sin 10x

so the answer is A.

identity: sin(A+B) = sinA cosB + cosA sinB

Answer 6

but there is a negative sign in between!

Answer 7

So it wouldnt be A? @hartnn

Answer 8

A ????
you didn't list any choices

Answer 9

sin 7x

cos 7x

cos 9x

sin 9x

Answer 10

and he just copied the answer from somewhere....

Answer 11

oh..

Answer 12

\(\Large \sin 8x \cos x - \cos 8x \sin x = \sin(8x-x) = ...\)

Answer 13

sin7x

Answer 14

correct! :)