# Math Help - Lengths of Plane Curves

1. ## Lengths of Plane Curves

Find the length of the curve:
x= (y^4)/4 + 1/(8y^2) from y=1 to y=2

I'm having trouble finding dx/dy

2. Originally Posted by TAG16
Find the length of the curve:
x= (y^4)/4 + 1/(8y^2) from y=1 to y=2

I'm having trouble finding dx/dy
$y = \frac{1}{4}y^4 + \frac{1}{8}y^{-2}$

$\frac{dx}{dy} = y^3 - \frac{1}{4y^3}$

can you finish?

3. yeah, thats actually what I had I just didn't think I was right. thanks