Precalculus: Mathematics for Calculus, 7th Edition

Published by Brooks Cole
ISBN 10: 1305071751
ISBN 13: 978-1-30507-175-9

Chapter 4 - Section 4.5 - Exponential and Logarithmic Functions - 4.5 Exercises - Page 369: 100

Answer

a. $T=200e^{-0.11t}+20$ b. $42.$2 ${}^{o}F$.

Work Step by Step

a. $\displaystyle \ln(\frac{T-20}{200})=-0.11t \qquad$ .. apply $e^{(..)}$ to both sides $\displaystyle \frac{T-20}{200}=e^{-0.11t}\qquad$ .. /$\times 200$ $T-20=200e^{-0.11t} \qquad$ .. /$+20$ $T=200e^{-0.11t}+20$ b. When $t=20,$ $T=200e^{-0.11(20)}+20$ $=200e^{-2.2}+20\approx 42.$2 ${}^{o}F$.
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.