Let $f ( x ) = \sqrt { x ^ { 2 } + 5 }$. 

1. Graph the function for $1\le x\le6$.

   Hint:

   This is not a parent function, so use a graphing calculator to generate the curve.

2. Find upper and lower approximations for the area by using five right-endpoint and five left-endpoint rectangles.

   Left endpoint hint:

   $\text{L}=1(f(1)+\dots+f(5))$

   Right endpoint hint:

   $\text{R}=1(f(2)+\dots+f(6))$