How do you differentiate (y^2+1)^2-x=0?

1 Answer
Apr 10, 2018

The implicit derivative dy/dx is 1/(4y(y^2+1)).

Explanation:

First, rearrange a little:

(y^2+1)^2-x=0

(y^2+1)^2=x

Now, take the implicit derivative (which basically means treat y as a function of x):

d/dx[(y^2+1)^2]=d/dx[x]

d/dx[(y^2+1)^2]=1

Power rule and chain rule:

2(y^2+1)^(2-1)*d/dx[y^2-1]=1

2(y^2+1)^(1)*d/dx[y^2-1]=1

2(y^2+1)*d/dx[y^2-1]=1

d/dx[y^2-1]=1/(2(y^2+1))

dy/dx*2y=1/(2(y^2+1))

dy/dx=(1/(2(y^2+1)))/(2y)

dy/dx=1/(4y(y^2+1))

That's the derivative. Hope this helped!