If i have a question saying find the exact value of cos 2 theta given that sin theta = - 3/5 and theta is in quadrant III. answear is 7/25 but I don't know how to get there explain and I will give you a huge THANKS!
Follow Math Help Forum on Facebook and Google+
$\displaystyle \cos 2\theta =1-2\sin^2\theta$ Then replace $\displaystyle \sin\theta$ with $\displaystyle -\frac{3}{5}$
View Tag Cloud