Evaluate the expression under the given conditions. sin(𝜃 + 𝜑); sin(𝜃) = 15 /17 , 𝜃 in Quadrant I, cos(𝜑) -2 sqrt5/5 , 𝜑 in Quadrant II

Answer 1

Use Pythagoras to determine

If sin θ = 15/17 in QI, then cos θ = ?

If cos θ = (-2√5)/5 in QIII, then sin θ = ?∉

Now substitute in sine of sums formula.