Calculus 8th Edition

Published by Cengage
ISBN 10: 1285740629
ISBN 13: 978-1-28574-062-1

Chapter 4 - Integrals - Review - Exercises - Page 349: 9

Answer

$g(4)=3$ $g'(4)=0$

Work Step by Step

$g(x)=\int_{0}^{x}f(t)dt$ $g(4)=\int_{0}^{4}f(t)dt$ Since $1$ is between $0$ and $4$ it follows: $g(4)=\int_{0}^{1}f(t)dt+\int_{1}^{4}f(t)dt$ From the graph of $f$, the integral $\int_{0}^{1}f(t)dt$ represents the area of the region bounded between $f$, $t$ axis on $[0,1]$ which is the right triangle with heigh $2$ units and base $1$ unit. $\int_{0}^{1}f(t)dt=\frac{1}{2} \cdot 2 \cdot 1=1$ Since the the function $f$ is negative on $[0,1]$ it follows that the integral of $f$ on $[0,1]$ is negative so: $\int_{0}^{1}f(t)dt=-1$ From the graph of $f$, the integral $\int_{1}^{4}f(t)dt$ represents the area of the region bounded between $f$, $t$ axis on $[1,4]$ which is the trapezoid with heigh $2$ units and bases $3$ unit and $1$ unit. $\int_{1}^{4}f(t)dt=\frac{1}{2} \cdot 2 \cdot (3+1)=4$ $g(4)=\int_{0}^{1}f(t)dt+\int_{1}^{4}f(t)dt \to g(4)=-1+4=3 $ ------------------------------------------------------------------ $g(x)=\int_{0}^{x}f(t)dt$ Using the fundamental theorem of calculus it follows: $g'(x)=f(t)$ Substitute $x=4$ into the equation: $g'(4)=f(4)$ From the graph of $f$, the value of $f(4)$ is $0$. So: $g'(4)=0$
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.