Question
upstudy study bank question image url

Determine the average value of the piecewise function \( f \) defined below on the interval \( x=-1 \) to \( x=2 \). Express your answer in simplest form. \[ f(x)=\left\{\begin{array}{lll}-6 x^{2} & \text { for } & x<0 \\ -8 x+6 & \text { for } & x \geq 0\end{array}\right. \]

Ask by Griffiths Davey. in the United States
Jan 23,2025

Real Tutor Solution

Tutor-Verified Answer

Answer

The average value of the function \( f(x) \) on the interval from \( x = -1 \) to \( x = 2 \) is \(-2\).

Solution

To determine the average value of the piecewise function \( f(x) \) on the interval \( x = -1 \) to \( x = 2 \), follow these steps: 1. **Understand the Average Value Formula:** The average value of a function \( f(x) \) over an interval \([a, b]\) is given by: \[ \text{Average value} = \frac{1}{b - a} \int_{a}^{b} f(x) \, dx \] 2. **Break the Integral into Parts:** Since \( f(x) \) is defined differently for \( x < 0 \) and \( x \geq 0 \), split the integral at \( x = 0 \): \[ \int_{-1}^{2} f(x) \, dx = \int_{-1}^{0} (-6x^2) \, dx + \int_{0}^{2} (-8x + 6) \, dx \] 3. **Evaluate the Integrals:** - **First Integral (\( x \) from -1 to 0):** \[ \int_{-1}^{0} (-6x^2) \, dx = -6 \left( \frac{x^3}{3} \right) \Big|_{-1}^{0} = -2x^3 \Big|_{-1}^{0} = -2(0)^3 - (-2(-1)^3) = -2 \] - **Second Integral (\( x \) from 0 to 2):** \[ \int_{0}^{2} (-8x + 6) \, dx = \left( -4x^2 + 6x \right) \Big|_{0}^{2} = (-16 + 12) - (0) = -4 \] 4. **Sum the Integrals and Compute the Average:** \[ \text{Total integral} = -2 + (-4) = -6 \] \[ \text{Average value} = \frac{-6}{2 - (-1)} = \frac{-6}{3} = -2 \] **Thus, the average value of \( f(x) \) on the interval from \( x = -1 \) to \( x = 2 \) is \(-2\).** \(-2\)

Reviewed and approved by the UpStudy tutoring team

error msg
Explain
Simplify this solution

The Deep Dive

To determine the average value of the piecewise function \( f(x) \) on the interval \( x = -1 \) to \( x = 2 \), we first calculate the average value using the formula: \[ \text{Average value} = \frac{1}{b-a} \int_a^b f(x) \, dx \] In this case, \( a = -1 \) and \( b = 2 \). ### Step 1: Calculate the integral of \( f(x) \). We split the integral at the point where the definition of \( f(x) \) changes, which is at \( x = 0 \): \[ \int_{-1}^2 f(x) \, dx = \int_{-1}^0 f(x) \, dx + \int_{0}^2 f(x) \, dx \] ### For \( x < 0 \) (from -1 to 0): Here, \( f(x) = -6x^2 \), so we evaluate: \[ \int_{-1}^0 -6x^2 \, dx \] Calculating this integral: \[ = -6 \int_{-1}^0 x^2 \, dx = -6 \left[ \frac{x^3}{3} \right]_{-1}^0 = -6 \left( 0 - \frac{(-1)^3}{3} \right) = -6 \left( 0 + \frac{1}{3} \right) = -2 \] ### For \( x \geq 0 \) (from 0 to 2): Here, \( f(x) = -8x + 6 \), so we evaluate: \[ \int_{0}^2 (-8x + 6) \, dx \] Calculating this integral: \[ = \left[ -4x^2 + 6x \right]_{0}^2 = \left( -4(2^2) + 6(2) \right) - \left( -4(0^2) + 6(0) \right) = (-16 + 12) - 0 = -4 \] ### Step 2: Combine the results from both intervals: Now we combine the integrals: \[ \int_{-1}^2 f(x) \, dx = -2 + (-4) = -6 \] ### Step 3: Find the average value: Now we apply the average value formula: \[ \text{Average value} = \frac{1}{2 - (-1)} \int_{-1}^2 f(x) \, dx = \frac{1}{3} \times (-6) = -2 \] Thus, the average value of the piecewise function \( f \) on the interval from \( x = -1 \) to \( x = 2 \) is \[ \boxed{-2} \]

Try Premium now!
Try Premium and ask Thoth AI unlimited math questions now!
Maybe later Go Premium
Study can be a real struggle
Why not UpStudy it?
Select your plan below
Premium

You can enjoy

Start now
  • Step-by-step explanations
  • 24/7 expert live tutors
  • Unlimited number of questions
  • No interruptions
  • Full access to Answer and Solution
  • Full Access to PDF Chat, UpStudy Chat, Browsing Chat
Basic

Totally free but limited

  • Limited Solution
Welcome to UpStudy!
Please sign in to continue the Thoth AI Chat journey
Continue with Email
Or continue with
By clicking “Sign in”, you agree to our Terms of Use & Privacy Policy