Question

prove the following identity: (sin^3 y -1)/(sin y -1) = sin^2 y + sin y + 1

Answer 1

this has nothing whatsoever to do with trig. use
\[\frac{a^3-1}{a-1}=\frac{(a-1)(a^2+a+1}{a-1}=a^2+a+1\] replace
\[a\] by
\[\sin(y)\] so get your answer

Answer 2

ha you forgot to put a closing parenthesis

Answer 3

grrr