# How do you find the derivative of f(x)=1-2x^2?

Jun 16, 2017

$\frac{d}{\mathrm{dx}} = - 4 x$

#### Explanation:

We find the derivative using the power rule:

$\frac{d}{\mathrm{dx}} {x}^{n} = n {x}^{n - 1}$

Simply to put it into words bring down the exponent and multiply it by the n (n in our case is equal to $2$) and subtract 1 from the exponent.

The derivative of a constant is always zero:

$\frac{d}{\mathrm{dx}} c = 0$

Knowing this we can now move forward:

$f ' \left(x\right) = \frac{d}{\mathrm{dx}} 1 - \frac{d}{\mathrm{dx}} 2 {x}^{2}$

$f ' \left(x\right) = 0 - 2 \left(2\right) {x}^{2 - 1}$

$f ' \left(x\right) = - 4 x$