$42,43$ and $44$ please. Use the sum of the first $10$ terms to approximate the sum of the series. Estimate the error. Thank you

$42.{\displaystyle \underset{n=1}{\overset{}{}}}\frac{e^{\frac{1}{n}}}{n^4}$

$43.{\displaystyle \underset{n=1}{\overset{}{}}}{5}^{-n}co{s}^{2}n$

$44.{\displaystyle \underset{n=1}{\overset{}{}}}\frac{1}{3^n+4^n}$