.I can do the problem, but my final number is wrong.

First we need to parametrize;

This means that the individual parametric equations are,

The next step is to integrate;

The problem:

Here it must be

Tonio

So if you do that last line you should end up with a...(19),using the FTC 'b-a'. Of course in this case b=1,a=0.

However, when I make it -19 I'm told I'm am correct; what have I done wrong to end up with the wrong sign.