Use the diagram below to answer the following questions.

$($a$)$ Write out a definite integral that rep$-$

resents the area of the shaded region

given in the diagram. Be sure to in$-$

clude all the correct elements of a def$-$

inite integral.

$($b$)$ Find the area by evaluating the defi$-$

nite integral demonstrating the FTC$.$

Your answer must be exact values.

Do not use a calculator to approxi$-$

mate the answer.