If sinx=3/5,siny=−12/13,x in quad I, y in quad. III, find: a. sin(x+y) b. cos(x+y) c. tan(x+y)

Answer 1

From the sinx=3/5, sin^-1(3/5) x = 36.870º

From the siny= -12/13 sin^-1 (-12/13) y = 247.380°

Sin (x+y) = -,969

Cos (x+y) = .246

Tan (x+y) = -3.938

Answer 2

Either draw and label a diagram to determine cos x and cos y.

Or

Use Pythagoras to determine the same.

Then substitute values into appropriate formula.