i need help on this practice exam, please help and please teach me with full explanation. thank you

3. (21 points} Find a power series for the function, and the radius of convergence (a) for) = 5" 2x+6 (b) f(x) = V1 22: (write the first five terms) (a: for) = xrmn'ltxZ) 4. (15 points) Find the sum of the series. (a) 310 (_1)n..2n+1 32n+1(2n+1)! Tr\" (b) 23:0 5n+1 2 712-1 (C) 230:2