### Home > CALC > Chapter 3 > Lesson 3.3.4 > Problem3-134

3-134.

For each of the following, find the second derivative with respect to $x$.

1. $y = 8x^{99}$

$y=8x^{99}$
$\frac{dy}{dx}=(99)8x^{98}=792x^{98}$
$\frac{d^{2}y}{dx^{2}}=\underline{ \ \ \ \ \ \ \ }$

$(98)(99)8x^{97} = 77,616x^{97}$

1. $y = - 3 \sqrt { x }$

Refer to part (a) for further guidance. Remember to rewrite the square root with an exponent before proceeding.

1. $f ( x ) = \frac { 2 } { 3 } x - 6 x ^ { - 2 }$

Refer to part (a) for further guidance.

1. $f(x) = 7 − 2\text{ cos }x$

Refer to part (a) for further guidance.