- #1

- 97

- 0

## Homework Statement

http://gyazo.com/d875970963124b7d4a64acc887f168fa

## The Attempt at a Solution

I dont understand the part where they take the derivative of a diff eq to find the higher derivatives can somebody explain it?

Mainly the answer where they get

y''=(y'')'=(1-y^2)'=-2yy'(this part)

y^(4)=(y''')'=(-2yy')'=-2y'y'-2yy"(huh?)=-2(y')^2-2yy''