Posted by t54 on .
sin(15)
tan(165)

advanced math 
Reiny,
I bet it said "find the exact value"
sin(15) = sin(3045)
= sin30cos45  cos30sin45
= (1/2)(√2/2)  (√3/2)(√2/2) = (√2  √6)/4
tan(165) = tan(120+45)
= (tan120 + tan45)/(1tan120tan45)
tan 120 = tan60 = √3
so back into the above result
= (√3 + 1)/(1  (√3)(1)) = (1√3)/(1+√3)