Prove an improper double integral is convergent I need to prove the following integral is convergent and find an upper bound
$$\int_{0}^{\infty} \int_{0}^{\infty} \frac{1}{1+x^2+y^4} dx dy$$
I've tried integrating $\frac{1}{1+x^2+y^2} \lt \frac{1}{1+x^2+y^4}$ but it doesn't converge

Finding the exact value of $\int_0^\infty\frac{dx}{a^2+x^2}$ is just a calc I exercise. Let $a=\sqrt{1+y^4}$ and see what happens...
