In x Evaluate the integral using integration by parts: - dx. Solution. First, find In x - dx 1 4 Set U = du = dx du= dx U = then In x 4 dx = udu = uv - | udu = +C where C is a constant. Now, we have In x dx =Use substitution to evaluate the integral dx. x2 + 36 Solution. Set U= du = dx Then, we obtain dx = x2 + 36 du = +C - a function in the variable u = +C a function in the variable x where C is a constant