We know from the pythagorean theorem:
sin^2(x) + cos^2(x) = 1
Subtract sin^2(x) from each side and we get:
cos^2(x) = 1 - sin^2(x)
We can rewrite our original expression as:
sin^2(x)/cos^2(x)
But this expression equals tan^2(x)
sin^2(x) + cos^2(x) = 1
Subtract sin^2(x) from each side and we get:
cos^2(x) = 1 - sin^2(x)
We can rewrite our original expression as:
sin^2(x)/cos^2(x)
But this expression equals tan^2(x)