Question 645341
if cos(theta) = -1/3 and theta is in quadrant 3. Evaluate sin2(theta)
use x for theta

given cosx=-1/3=adj side/hypotenuse
opp side =-√[(hypotenuse^2)-(adj side^2)]=-√(9-1)=-√8
sinx=-√8/3
sin(2x)=2sinxcosx=2*-√8/3*-1/3=2√8/9=4√2/9