Estimate the area under the graph of $\displaystyle {f{{\left({x}\right)}}}=\frac{{1}}{{{x}+{4}}}$ over the interval $\displaystyle {\left[-{1},{2}\right]}$ using ten approximating rectangles and right endpoints.

$\displaystyle {R}_{{n}}=$

Repeat the approximation using left endpoints.

$\displaystyle {L}_{{n}}=$

Report answers accurate to 4 places. Remember not to round too early in your calculations.