Ignore this post, found the mistake

$$\int_{1}^{4}\frac{1}{x^{(3/2)}+x}dx = \int_{1}^{4}\frac{1}{\sqrt{x}*x+x}dx$$

Subsitution:

$$t=\sqrt{x}$$

$$dt=\frac{1}{2t}dx$$

$$\int_{1}^{2}\frac{2t}{t*t^2+t}dt = 2\int_{1}^{2}\frac{1}{t^2+1}dt = 2arctan(2) - 2arctan(1)$$

Why is the above wrong?