Question

I need answers please..
1 - cos(6x)= ____ ..
A: 3sin(2x)
B: 2cos^2(3x)
C: 2sin^2(3x)
D: 3cos(2x)

And http://prntscr.com/6nvdjs

Answer 1

you might want to review your trig identities for double and half angles ... and this is a tutoring site, not a free answering service.

Answer 2

7 looks like you made an attempt so we can go over that one at least

Answer 3

sincos is from the sin double angle formula, these formulas basically need to be remembered otherwise youd need to know how to find them from a more complicated drawing

sin(a+b) = sina cosb + sinb cosa

now when a=b this is just

sin(2a) = 2sina cosa

Answer 4

a constant in front is therefore doubled, or halved if you back it up

Answer 5

Yeaa I havent studied at all in this class, I have no idea what any of that means

Answer 6

its just stating how to use the formula ....

Answer 7

On number 7 right?

Answer 8

yes, on number 7 since it looks like an attempt was made for it at least :)

k sin(2a) = 2k sin(a) cos(a)

if k = 1/32, then 2k = 1/16

1/32 sin(2a) = 1/16 sin(a) cos(a) would fit the formulas

Answer 9

where did k or a come from

Answer 10

from the general setup

k is just some number, a constant

a is some angle

Answer 11

hmm..

Answer 12

since ive done all the work .... and have determined that:

1/32 sin(2a) = 1/16 sin(a) cos(a)

how can we relate this to your problem in 7?