Math Problem Statement

A company determines that its weekly online​ sales,

Upper S left parenthesis t right parenthesisS(t)​,

in hundreds of​ dollars, t weeks after online sales began can be estimated by the equation below. Find the average weekly sales for the first

5

weeks after online sales began.

Upper S left parenthesis t right parenthesisS(t)equals=5 e Superscript t5et

Question content area bottom

Part 1

The average weekly sales amount is

​$enter your response here.

​(Round to the nearest cent as​ needed.)

Solution

To find the average weekly sales over the first 5 weeks, we calculate the average value of the function S(t)S(t) over the interval [0,5][0, 5].

The formula for the average value of a function f(t)f(t) over [a,b][a, b] is:

Average value=1baabf(t)dt\text{Average value} = \frac{1}{b-a} \int_a^b f(t) \, dt

For the given equation S(t)=5etS(t) = 5e^t, a=0a = 0, and b=5b = 5, the calculation becomes:

Average sales=150055etdt\text{Average sales} = \frac{1}{5-0} \int_0^5 5e^t \, dt

Steps to Solve:

  1. Compute the integral of 5et5e^t: 5etdt=5et+C\int 5e^t \, dt = 5e^t + C

  2. Evaluate the definite integral from t=0t = 0 to t=5t = 5: 055etdt=[5et]05=5e55e0\int_0^5 5e^t \, dt = \left[ 5e^t \right]_0^5 = 5e^5 - 5e^0

  3. Simplify: 5e0=5and5e5=5×e55e^0 = 5 \quad \text{and} \quad 5e^5 = 5 \times e^5 Substitute e5148.413e^5 \approx 148.413: 5e55×148.413=742.0655e^5 \approx 5 \times 148.413 = 742.065 055etdt742.0655=737.065\int_0^5 5e^t \, dt \approx 742.065 - 5 = 737.065

  4. Divide by 5 to find the average: Average sales=737.0655147.41(hundreds of dollars)\text{Average sales} = \frac{737.065}{5} \approx 147.41 \, (\text{hundreds of dollars})

  5. Convert to dollars: Average sales=147.41×100=14,741.00\text{Average sales} = 147.41 \times 100 = 14,741.00

Final Answer:

The average weekly sales for the first 5 weeks is approximately $14,741.00.


Would you like further explanation on these steps or the concept of average value?

Related Questions:

  1. What is the instantaneous rate of sales at t=5t = 5?
  2. How does the average sales change if calculated for 10 weeks instead of 5?
  3. Can the equation be approximated with simpler exponential growth patterns?
  4. What is the total sales revenue accumulated in the first 5 weeks?
  5. How would the average change if the function had a coefficient other than 5?

Tip: When calculating definite integrals involving ete^t, remember that the exponential function is one of the easiest to differentiate and integrate.

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Math Problem Analysis

Mathematical Concepts

Calculus
Exponential Functions
Average Value of a Function
Definite Integration

Formulas

Average value of a function: Average = (1 / (b - a)) ∫_a^b f(t) dt
Integral of exponential function: ∫e^t dt = e^t + C

Theorems

Fundamental Theorem of Calculus

Suitable Grade Level

Grade 11-12 or College Level