12. Techniques of Integration

Which of the following integrals is improper?

Which of the following integrals is improper because the interval of integration is infinite?

Evaluate the integral or state that it diverges. 

${\int }_{-\infty }^{-1}\frac{2}{x^3}dx$

Evaluate the integral or state that it diverges. 

${\int }_2^{\infty }\frac{1}{x(lnx{)}^4}dx$