Question

sin(-15)

tan(165)

Answer 1

I bet it said "find the exact value"

sin(-15) = sin(30-45)
= sin30cos45 - cos30sin45
= (1/2)(√2/2) - (√3/2)(√2/2) = (√2 - √6)/4

tan(165) = tan(120+45)

= (tan120 + tan45)/(1-tan120tan45)

tan 120 = -tan60 = -√3

so back into the above result
= (-√3 + 1)/(1 - (-√3)(1)) = (1-√3)/(1+√3)