While trying to graph NINT, I keep getting the wrong graph.

I'm trying to graph$\displaystyle \sqrt{ 1 + sin^2 x}$ on the interval [0,3].

I first got a straight line graphing:

fnint(the function, x, 0, 3)

Then I looked at my book and changed the x-res to increase speed.

Now the function looked like an line that is increasing.

I had put in:

fnint(the function, x, 0, x)

What should I do?

Thanks!