1. The problem statement, all variables and given/known data The nth term for a sequence is the square root of [n/ (n^4 + 1)] Investigate whether it is convergence or divergence. 2. Relevant equations Ratio test and integral test 3. The attempt at a solution Ratio test will fail for this question, since no conclusion can be drawn if the ratio is 1. So I have to use integral test. I tried integrating the function using integration by part, bu that doesn't work. Trigonometric substitution fail as well. Any idea how to integrate the function?