So I could put the du either in the numerator, I could put it out here. And then I have one over, this is u squared, u squared plus one. Now you might immediately recognize, what's the derivative of arc tan of u? Well, that would be one over u squared plus one. So this is going to be equal to 1 1 0 times the arc tangent of u. And of course, we can't forget our big constant c, because we're taking an indefinite integral. And now we just wanna do the reverse substitution.