(Solved): Useful Sums: Refer to the web page class handout, "Useful Sums" (a useful reference for later in ou ...

Useful Sums: Refer to the web page class handout, "Useful Sums" (a useful reference for later in our course) for help on the problem below. Determine the closed form solution for the following sums. (Hint: Feel free to use variable substitution, when appropriate, to manipulate limits to fit sums defined on the web page handout): (a) ${?}_{k=1}^{100}(?2{)}^k$ (b) ${?}_{k=??}^2(3{)}^k$ (c) ${?}_{k=1}^{?}{\left(\frac{1}{3}+\frac{1}{3}j\right)}^k$ (d) ${?}_{k=10}^{?}(?a?{)}^k,?a?<1$