BuddyHawks

I have to find where these two functions intersect.

g(x) = sin(2x) & f(x) = sin(x)
so

sin(2x) = sin(x)

How do I solve for x?

need exact value, not decimal.
THANK YOU

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goateebird

0, and 180 (degrees) both work, just by intuition, and i think i know how to actually work it out, but my brain isn't really working right now, so hold up...

edit: woops, i said 90 instead of 180. mistake corrected.

KnifeMissile

Well, you should know the trigonometric identity, sin(2x) = 2 * sin(x) * cos(x).
This should be enough for you to solve the problem, yourself...

BuddyHawks

Hey Hey, look at that!
Thanks.
And yeah, I SHOULD know the identity, but havn't had trig in years. (I'm actually in calc, rotating regions around a line and taking the integral to find the volume of da' soild)
fun fun

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frozenstellar

sin(2x) = 2sin(x)cos(x)
cos(2x) = 2cos^2(x) - 1
cos(2x) = 1 - 2sin^2(x)
cos(2x) = cos^2(x) - sin^2(x)
tan(2x) = 2tan(x) / 1 - tan^2(x)

sin(x+y) = sin(x)cos(y) + cos(x)sin(y)
sin(x-y) = sin(x)cos(y) - cox(x)sin(y)

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

tan(x+y) = tan(x) + tan(y) / (1 - tan(x)tan(y))
tan(x-y) = tan(x) - tan(y) / (1 + tan(x)tan(y))

sin^2(x) = 0.5 - 0.5cos(2x)
cos^2(x) = 0.5cos(2x) - 0.5

i think they're all correct, havent had to think about any of it for 4months.. hope they are, that'd mean i'd have less to worry about this year