Question

without using calculator,find all the angles in between 0' and 360' which satisfy the following trigonometric equation.
sin3x=cos(90'-2x)

Answer 1

use the difference identity on cos (90-2x)

Answer 2

difference identity?

Answer 3

yeah, there's an identity for simplifying cos (a-b) to something else
but i'm too lazy to look it up today

Answer 4

and for the sin 3x
http://library.thinkquest.org/17119/media/3_211.gif

Answer 5

is it like that?
3sinx-4sin^3 x= cos90cos2x+sin90sin2x
3sinx-4sin^3 x=sin2x
3sinx-4sin^3 x -sin 2x=0

Answer 6

now use the double angle identity for sin 2x