Let $\displaystyle f(x) = 1 - 2x^{2}$ and determine

b) $\displaystyle f(1-\sqrt{3})$

I know that I´m supposed to put the above functions number 1 - squart 3 on the functions x place.

This is how far I´ve come:

I´m getting the number to

$\displaystyle f(1-\sqrt{3})$=$\displaystyle 1 - 2 (1-\sqrt{3})^{2}$

is this correct and if, what should I do now?