tan theta=-3/4 and 90<theta<180 Find sin2 theta

Question

Plz give me answer fast

Answer 1

Hi Timmy,

 

sin(2theta) = 2 sin(theta)cos(theta)

Theta is in the second quadrant so sin(theta) > 0 and cos(theta) < 0.

if tan(theta) = -3/4, then

sin(theta) = 3/5 and

cos(theta) = -4/5

sin(2theta) = 2*(3/5)*(-4/5)

= -24/25