Help with Series Problems

[LunarVoid]

Hello,

I'm struggling with a couple of series problems and I just don't know how to approach them. I have some work for the power series question, but I don't know if I'm on the right track. I am unsure of the other two. The last image is the work I have for the 3rd picture. Any help is appreciated. Thank you.

 

[Dr.Peterson]

For the first, if you have no idea, I would write out the first few terms to get a sense of what it looks like. You should be able to see what a and r are then.

Where you are unsure, it can still be very helpful to show us whatever ideas you have tried. Please do so.

 

[lookagain]

LunarVoid, also please post one problem per thread .