hey!
first off i'm new to this forum
got a few questions on my homework that I am stuck on. I represent the summation sign with a capital E. n! means n factorial
1) E (n! x^2n / (3n-1)!)
2) E (-3/sqrt(n))(x/2)^n
thanks a bunch if you help me out!
You mean "interval" of convergence. A fairly standard method of determining radius of convergence is to use the ratio test:
A series converges if the ratio .
For 1, and . The ratio is . Take the limit as n goes to infinity, set that < 1, and solve for x.
For 2, , . The ratio is . Again, take the limit as n goes to infinity, set it < 1, and solve for x.