f(x)=kx². [-1,1] = 1 (Type an exact answer.) he probability density function is f(x) = (Jyn

MATLAB: An Introduction with Applications
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Author:Amos Gilat
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### Finding the Probability Density Function

In this problem, we aim to determine the constant \( k \) such that the function \( f(x) \) is a probability density function over the interval \([-1, 1]\). The given function is:

\[ f(x) = kx^2 \]

#### Steps to Determine \( k \)

1. **Integrate \( f(x) \) over the interval \( [-1, 1] \)**:
   \[
   \int_{-1}^{1} kx^2 \, dx
   \]

2. **Ensure the integral equals 1** (as this is a requirement for the function to be a probability density function):
   \[
   \int_{-1}^{1} kx^2 \, dx = 1
   \]

Perform the integral calculation:
\[
\int_{-1}^{1} kx^2 \, dx = k \left[ \frac{x^3}{3} \right]_{-1}^{1} = k \left( \frac{1^3}{3} - \frac{(-1)^3}{3} \right) = k \left( \frac{1}{3} - \left( \frac{-1}{3} \right) \right) = k \left( \frac{1}{3} + \frac{1}{3} \right) = k \left( \frac{2}{3} \right)
\]

Thus, setting the integral equal to 1 for it to be a probability density function:
\[
k \left( \frac{2}{3} \right) = 1 \implies k = \frac{3}{2}
\]

#### Final Probability Density Function

Given \( k = \frac{3}{2} \), the probability density function \( f(x) \) is:

\[ f(x) = \frac{3}{2} x^2 \]

### Summary

After solving, we find:
- \( k = \frac{3}{2} \)
- The probability density function is \( f(x) = \frac{3}{2} x^2 \)

This ensures that \( f(x) \) satisfies the properties of a probability density function over the interval \([-1, 1]\).
Transcribed Image Text:### Finding the Probability Density Function In this problem, we aim to determine the constant \( k \) such that the function \( f(x) \) is a probability density function over the interval \([-1, 1]\). The given function is: \[ f(x) = kx^2 \] #### Steps to Determine \( k \) 1. **Integrate \( f(x) \) over the interval \( [-1, 1] \)**: \[ \int_{-1}^{1} kx^2 \, dx \] 2. **Ensure the integral equals 1** (as this is a requirement for the function to be a probability density function): \[ \int_{-1}^{1} kx^2 \, dx = 1 \] Perform the integral calculation: \[ \int_{-1}^{1} kx^2 \, dx = k \left[ \frac{x^3}{3} \right]_{-1}^{1} = k \left( \frac{1^3}{3} - \frac{(-1)^3}{3} \right) = k \left( \frac{1}{3} - \left( \frac{-1}{3} \right) \right) = k \left( \frac{1}{3} + \frac{1}{3} \right) = k \left( \frac{2}{3} \right) \] Thus, setting the integral equal to 1 for it to be a probability density function: \[ k \left( \frac{2}{3} \right) = 1 \implies k = \frac{3}{2} \] #### Final Probability Density Function Given \( k = \frac{3}{2} \), the probability density function \( f(x) \) is: \[ f(x) = \frac{3}{2} x^2 \] ### Summary After solving, we find: - \( k = \frac{3}{2} \) - The probability density function is \( f(x) = \frac{3}{2} x^2 \) This ensures that \( f(x) \) satisfies the properties of a probability density function over the interval \([-1, 1]\).
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