1)Can the following series be tested for convergence in the Integral Test. Why or why not?

1)Can the following series be tested for convergence in the Integral Test. Why or why not?A. series n=1 to infinity of: ln(1.9n)*The answer is NO because the terms in the sees do not decrease in magnitudeB. series n=1 to infinity of : (cos(pi*n))/(n^3)* The answer is no because the terms are not all positive for all n greater than or equal to cfor c>0C. series n=1 to infinity of: (n-7)^8 * 7^(-n)* The answer is no because the terms in the series do not decrease in magnitudePLEASE explain how these answers are achieved. I know you can use improper integrals but I don't know how to use them to get these answers.