I think I'm missing something. This seems relatively easy but I am not getting the right answer.

Find the arc length.

$\displaystyle y=5 + 6x^{\frac{3}{2}}$ for $\displaystyle 0\leq x\leq 1$

Using: $\displaystyle \int\limits^{b}_{a} \sqrt{1 + (f(x)')^2} dx$

I get:

$\displaystyle \int\limits^{1}_{0} \sqrt{(81x^{\frac{1}{4}}) +1}dx$

$\displaystyle \int\limits^{1}_{0} 9x^{\frac{1}{2} + 1}dx$

$\displaystyle = 6x^{\frac{3}{2}} + x$

Then when I evaluate at my limits, I get 7. Which is the wrong answer in Webassign. I also tried it using u-substitution and got like 54 for an answer.

CAn someone get me straight here?

Thanks!!