Any help/hints for any of these exercises would be much appreciated!

**3.** has a radius of convergence of

. Determine whether or not each endpoint converges.

**4.** has a radius of convergence of

. Determine whether or not each endpoint converges.

**5.** (with

negative integer) has a radius of convergence of

. Determine whether or not each endpoint converges.

Determining the radiuses of convergence for these series was easy, but I don't seem to have enough tools in my toolbox of math tricks to routinely solve the endpoints. I am therefore looking to learn new tricks! Please share them if you've got them.

Thanks!

EDIT: The following have been solved:

**1.** has a radius of convergence of

. Determine whether or not each endpoint converges.

**2.** has a radius of convergence of

. Determine whether or not each endpoint converges.