What Is the Correct Approach to Find the Centroid of a Parabolic Area?

[jesuslovesu]

[SOLVED] Centroid Parabolic area

Homework Statement

http://img227.imageshack.us/img227/7518/slowge9.th.jpg
Find the centroid of the area.

Homework Equations

The Attempt at a Solution

I'm not quite sure what I'm screwing up on this problem, I can do other problems like when y = x^2. I have only shown my work for the x centroid, but I can't seem to get the answer (3/8b). Does anyone see where I messed up, I assume it's somewhere in the integral setup. I think dA = h-y dx is correct.

 

[Shooting Star]

The point (b,h) lies on the curve. Doesn't that suggest something, like a relationship between them, which you can put in the answer?

 

[jesuslovesu]

Thanks for your reply, I figured it out