# trig

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If
cot(x) = −19/18
,
where x is in Quadrant IV, what is the exact value of sin(2x)?

• trig -

tan x = -18/19
hypotenuse = sqrt (18^2+19^2)
= sqrt (324+361)
= sqrt(685)
sin x = -18/sqrt(685)
cos x = +19/sqrt(685)

sin (2x) = 2 sin x cos x
= -2*18*19/685

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