Question 928571
given cos theta equals-3/5 with pi less than theta less than 3pi/2, find the exact value of tan(2theta)
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reference angle x is in quadrant II where cos<0, sin<0
cosx=-3/5
sinx=-4/5
tanx=sin/cos=4/3
{{{tan(2x)=(2tanx)/(1-tan^2(x))
=(8/3)/(1-(16/9))
=(24/9)/(9/9-(16/9))=(24/9)/(-7/9)=-24/7}}}