Compute the value of the improper integral. (If the integral diverges to oo, type oo; if it diverges to - co, type -oo; if it diverges for some other reason, type DNE.) 3 da = 1 + 2-2 Use the value of the improper integral to determine whether or not the series E 3 converges or n=1 1 + n2 diverges. Enter C if the series is convergent, D if the series is divergent, and ? if the Integral Test does not apply