Is $f (x) = - 2 x^{2} - 2 x - 1$ $f(x)=-2x^2-2x-1$ increasing or decreasing at $x = - 1$ $x=-1$ ?

Question

2813 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2015-12-18T12:25:36

It is increasing at $x = - 1$ $x=-1$ .

$\times f (x) = - 2 x^{2} - 2 x - 1$ $color(white)(xx)f(x)=-2x^2-2x-1$

$=>f'(x)=-4x-2$
$=>f'(-1)=4-2$
$color(white)(xxxxxxxx)=2$

$=>f'(-1)>0$

Therefore $f(x)$ is increasing at $x=-1$ .
graph{-2x^2-2x-1 [-10, 10, -5, 5]}

Is f(x)=-2x^2-2x-1f(x)=−2x2−2x−1f(x)=-2x^2-2x-1 increasing or decreasing at x=-1x=−1x=-1?