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Mathematics 18 Online
OpenStudy (thatonegirl_):

Idk what I keep doing wrong.. Find the exact values of sin2a, cos2a, and tan2a. Sina=-2/3, π

rishavraj (rishavraj):

sin a = -2/3 |dw:1432081708124:dw|

OpenStudy (thatonegirl_):

But how do i plug it into the double-angle formula?

OpenStudy (thatonegirl_):

Dw dw no one knows how to do this crap -.-

rishavraj (rishavraj):

sin (2a) = 2sin a cos a cos 2a = 2cos^2 a - 1

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