To simplify the given expression, we can use the trigonometric identity:
sin^2(a) + cos^2(a) = 1
Now, let's rewrite the expression:
sin^2(a)/cos^2(a) - sin^2(a)
= (sin^2(a) - sin^2(a)cos^2(a))/cos^2(a)
= sin^2(a)(1-cos^2(a))/cos^2(a)
= sin^2(a)sin^2(a)/cos^2(a)
= sin^4(a)/cos^2(a)
To simplify the given expression, we can use the trigonometric identity:
sin^2(a) + cos^2(a) = 1
Now, let's rewrite the expression:
sin^2(a)/cos^2(a) - sin^2(a)
= (sin^2(a) - sin^2(a)cos^2(a))/cos^2(a)
= sin^2(a)(1-cos^2(a))/cos^2(a)
= sin^2(a)sin^2(a)/cos^2(a)
= sin^4(a)/cos^2(a)