3.9 Improper integrals

1.

(a) $2$(b) divergence (c) $-1$

2.

(a) $1$(b) convergence for $\alpha > 1$, divergence for $\alpha \leq 1$(c) convergence for $\alpha > 1$，divergence for $\alpha \leq 1$

3.

(a) convergence $${\frac{\sqrt{\pi} \Gamma({1}/{4})}{2 \Gamma ({3/4})}}$$(b) convergence $-4$