Solve the problem.
-A certain company has found that its expenditure rate per day (in hundreds of dollars) on a certain type of job is given by $E^{\prime}(x)=8 x+7$, where $x$ is the number of days since the start of the job. Find the expenditure if the job takes 5 days.
A) $\$ 47$
B) $\$ 4700$
C) $\$ 13,500$
D) $\$ 135$

Question

Quizplus · Accepted Answer

To find the total expenditure, integrate the rate function $E^{\prime}(x)=8x+7$ from 0 to 5. The integral is $\int_{0}^{5} (8x + 7) \, dx = [4x^2 + 7x]_{0}^{5} = (4(5)^2 + 7(5)) - (4(0)^2 + 7(0)) = 100 + 35 = 135$. Since the rate is in hundreds of dollars, the total expenditure is $135 \times 100 = \$13,500$.

Solve the Problem E′(x)=8x+7E^{\prime}(x)=8 x+7E′(x)=8x+7 , Where xxx Is the Number of Days Since the Start of the Expenditure

Solve the Problem $E^{\prime}(x)=8 x+7$ , Where $x$ Is the Number of Days Since the Start of the Expenditure