trig
posted by susmita on .
If tan A = 2 and A belongs to [pie,3pie/2] then the expression cos A divided by sin cubed A +cos cubed A is equal to what?

tanA = 2 in QIII means
sinA = 2/√5
cosA = 1/√5
cosA/(sin^3A + cos^3A)
= 1/√5 / (8/5√5  1/5√5)
= 1/√5 / (9/5√5)
= 1/√5 * 5√5/9
= 5/9
that's PI, not PIE!