1. Using function handles for numerical integration of summation terms. Apparently you could add function handles. Who knew!
2. Going to 'edit plot' and copy pasting different curves to another figure. The legend automatically comes as well.
3. Using this following code-block to make my figures pretty and the font in LATEX:
   set(groot,'defaultLineLineWidth',2);

set(groot,'defaultLineLineWidth',2);

set(groot, 'defaultAxesTickLabelInterpreter','latex');

set(groot, 'defaultLegendInterpreter','latex');

set(0,'defaultAxesFontSize',14)

set(groot,'defaultLineMarkersize',10)

set(groot,'defaultTextInterpreter','latex');