Question 927644
Hint: 


{{{sin(2x) = 2*sin(x)*cos(x)}}}



{{{sin(2x)/2 = sin(x)*cos(x)}}}



{{{sin(x)*cos(x) = sin(2x)/2}}}



hopefully that is enough to help you finish the problem off. If not, then please let me know.


Also, I'm assuming the original equation <i>should</i> be {{{(cos^3(b)+sin^3(b))/(cos(b)+sin(b)) = (2-sin(2b))/2}}} (notice how I have {{{cos^3(b)}}} and NOT {{{cos^3(a)}}})