Question 664418
How to prove the identity (sin^3@-cos^3@)/(sin@-cos@) = 1+sin@cos@ 
@=theta
**
(sin^3-cos^3)/(sin-cos)=1+sincos
start with left side
(sin^3-cos^3)/(sin-cos)
difference of cubes
=[(sin-cos)(sin^2+sincos+cos^2)]/(sin-cos)
sin^2+cos^2=1
=1+sincos
verified: left side=right side