$\sin^2 x \cos^2 x + \sin x \cos x -1 = 0$ 
$\sin^2 x \cos^2 x +  \sin x \cos x -1 = 0$

Attempt:
$\sin^2 2x + 2\sin 2x -4 = 0 \\ \implies \sin 2x= \sqrt 5 - 1$
Now, using the formula $\sin 2 x = \dfrac {2\tan x}{1+\tan^2x}$, I couldn't express the answer in terms of $\tan()$
The answer given is in terms of tan. How do I express it in that way? 

Hint:
Observe the roots of $t^2+2t-4=0$ are $-1\pm\sqrt 5$ (no denominator), and their absolute values are greater than $1$.
