help on trig identity containing fractions and a one

sifaka · #1 $Old$ November 3rd, 2009, 08:55 PM

$\frac{\frac{cos^2B}{sin^2B}-cos^2B}{\frac{1}{sin^2B}-1}=?cos^2B$
My real problems is that I can't see what to do with the expression containing both fractions and an integer, divided by another expression containing a fraction and an integer. Can you point me in the right direction?
~sif

pickslides · #2 $Old$ November 3rd, 2009, 09:21 PM

$1 = \sin^2(B)+\cos^2(B)$

That will take care of the integer.