- #1

- 41

- 0

## Homework Statement

y=sqrt(x^2-1) find d^2y / dx^2

## Homework Equations

power rule

## The Attempt at a Solution

(x^2 - 1)^1/2

y`=1/2(x^2 - 1)^-1/2

y``= 1/2 * -1/2 (x^2 - 1)^-3/2

y``= -1 / 4(x^2 - 1)^3/2

Why does my book give the same answer without the 4 in the denominator? Doesn't find d^2y / dx^2 just mean find y``?