# Simple trigonometry simplification

$\dfrac{(1-\sec^4\theta)(1-\sin^4\theta)}{\sin^2\theta-2}$

When simplifying the expressions above, how can I eliminate the denominator?

I have tried expanding the nominators by $a^4-1=(a^2-1)(a^2+1)$ but I still cannot remove that obstacle. Can anyone give me some hints to deal with the denominator?

Hint: I observe that ${\sin^2\theta-2} = {-(\cos^2\theta + 1)}$, which will (with a factor modification) cancel with one of those factors you might see from the numerator.