posted by Corin .
How do you verify:
I tried starting from the left on both problems, but am stuck.
like I said before, change everything into sines and cosines.
for the first one:
LS= sinxcosx + (sin^3x)cosx
=(sinxcos^2x + sin^3x)/cosx
factor out the sinx, and look what you have left inside the bracket!
two more steps!
the second one is just as easy.
LS = (1/cosx + sinx/cosx)(1/cosx - sinx/cosx)
can you see the common factor, and the difference of squares pattern?