Calculate the arc length along the curve x = y^4/4 + 1/8y^2 from y = 1 to y =2
You have x as a function of y instead of the other way, which might get a little confusing.
The formula for arc length is:
You just have to get the derivative, plug in, and do the integration. The limits are just y=1 to 2. It should be pretty straightforward.
Post again in this thread if you hit a roadblock.