Question

Help please.

Answer 1

Rewrite with only sin x and cos x.

sin 3x - cos x

Answer 2

use standrd formula
sin 3x = 3 sinx-4sin^3 x

Answer 3

yes, u do.

Answer 4

:)

Answer 5

gt it @keelyjm ?

Answer 6

do I put 3sinx-4cos^3x in place of 3 sinx and then solve?

Answer 7

@AravindG

Answer 8

in place of sin 3x yes

Answer 9

@keelyjm

Answer 10

now i observed!
its sin 3x = 3 sinx-4sin^3 x
not cos term
put this in sin 3x - cos x

Answer 11

so 3 sinx-4sin^3 x -cosx?

Answer 12

oh ya it sin^3x

Answer 13

sin 3x = 3 sinx-4sin^3 x

Answer 14

3 sinx-4sin^3 x -cosx
i think thats it...

Answer 15

Well it is a multiple choice and the choices are:
2 sin x - sin3x - cos x

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

2 sin3x cos4x + 1

3 sin x cos x - sin3x - cos x

Answer 16

but I am not sure becsue there are no similar terms...

Answer 17

weird becaus options have sin3x and question says
'only sin x and cos x.'

Answer 18

that is what I thought...

Answer 19

OOOOHH I wrote It wrong!! The answer choices are:
2 sin x - sin^3x - cos x

2 sin x cos^2x + sin x - 2 sin^3x - cos x

2 sin^3x cos^4x + 1

3 sin x cos x - sin^3x - cos x

Answer 20

@hartnn sorry my bad..

Answer 21

I think it is 2 sin^3x cos^4x + 1

Answer 22

i think it'll be
2 sin x cos^2x + sin x - 2 sin^3x - cos x
but let me try

Answer 23

3s -4 s^3 = 2s (1-s^2) -2s^3+s
= 2sc^2-2s^3+s
where s=sin x

Answer 24

c= cos x
so,
2 sin x cos^2x + sin x - 2 sin^3x - cos x = sin 3x - cos x

Answer 25

I see! Thanks for all of your help!