Trigonometry
Find the exact value of tan(x+y)\tan\left(x+y\right)tan(x+y) . Use a trigonometric identity.
cosx=511\cos x=\frac{5}{11}cosx=115, siny=−18\sin y=-\frac18siny=−81, xxx in fourth quadrant, yyy in third quadrant
−12806+36371479\frac{-1280\sqrt6+363\sqrt7}{1479}1479−12806+3637
11357\frac{11\sqrt3}{57}57113
−12806−36371479\frac{-1280\sqrt6-363\sqrt7}{1479}1479−12806−3637
−11357-\frac{11\sqrt3}{57}−57113