Question
upstudy study bank question image url

Find the critical numbers, the intervals on which \( f(x) \) is increasing, the \( f(x)=\frac{x^{2}}{x-5} \) Select the correct choice below and, if necessary, fill in the answer b A. The critical number(s) of the function are \( x=\square \). (Use a comma lo separate answers as necded.) B. There is no solution. Select the correct choice below and, if necessary, fill in the answer b A. The function is increasing on \( \square \). B. There is no solution.

Ask by Peters Campbell. in the United States
Mar 10,2025

Upstudy AI Solution

Tutor-Verified Answer

Answer

A. The critical numbers are \(0\) and \(10\). B. The function is increasing on \((-\infty, 0)\) and \((10, \infty)\).

Solution

We begin with the function \[ f(x)=\frac{x^2}{x-5}. \] Note that the domain is all real numbers except \(x=5\) (since the denominator cannot be zero). **Step 1. Compute the derivative \(f'(x)\).** Using the quotient rule, if \[ f(x)=\frac{u(x)}{v(x)}, \] then \[ f'(x)=\frac{u'(x)v(x)-u(x)v'(x)}{[v(x)]^2}. \] Here, \[ u(x)=x^2, \quad u'(x)=2x, \quad v(x)=x-5, \quad v'(x)=1. \] So, \[ f'(x)=\frac{2x(x-5)-x^2\cdot 1}{(x-5)^2}=\frac{2x(x-5)-x^2}{(x-5)^2}. \] Simplify the numerator: \[ 2x(x-5)-x^2=2x^2-10x-x^2=x^2-10x. \] Thus, \[ f'(x)=\frac{x^2-10x}{(x-5)^2}=\frac{x(x-10)}{(x-5)^2}. \] **Step 2. Find the critical numbers.** Critical numbers occur when \(f'(x)=0\) or when \(f'(x)\) is undefined (provided the point is in the domain). 1. \(f'(x)=0\) when the numerator is zero: \[ x(x-10)=0 \quad \Longrightarrow \quad x=0 \quad \text{or} \quad x=10. \] 2. \(f'(x)\) is undefined when the denominator is zero: \[ (x-5)^2=0 \quad \Longrightarrow \quad x=5. \] However, \(x=5\) is not in the domain of \(f\). Thus, the critical numbers are: \[ x=0 \quad \text{and} \quad x=10. \] **Step 3. Determine where \(f(x)\) is increasing.** The function is increasing where \(f'(x) > 0\). Since the denominator \((x-5)^2\) is always positive (except at \(x=5\) where \(f\) is not defined), the sign of \(f'(x)\) is determined by the numerator \(x(x-10)\). Solve the inequality: \[ x(x-10)>0. \] This product is positive when: - Both factors are positive: \(x>0\) and \(x-10>0\) which gives \(x>10\). - Both factors are negative: \(x<0\) and \(x-10<0\) which gives \(x<0\). Thus, \(f(x)\) is increasing on: \[ (-\infty,0) \quad \text{and} \quad (10,\infty). \] **Final Answers** A. The critical number(s) of the function are \(0, 10\). B. The function is increasing on \((-\infty, 0)\) and \((10, \infty)\).

Answered by UpStudy AI and reviewed by a Professional Tutor

error msg
Explain
Simplify this solution

Mind Expander

To find the critical numbers of the function \( f(x)=\frac{x^{2}}{x-5} \), we first need to find the derivative \( f'(x) \) and set it equal to zero. Calculating the derivative using the quotient rule yields: \[ f'(x) = \frac{(x-5)(2x) - x^2(1)}{(x-5)^2} = \frac{2x^2 - 10x - x^2}{(x-5)^2} = \frac{x^2 - 10x}{(x-5)^2} \] Setting the numerator equal to zero gives \( x^2 - 10x = 0 \) which factors to \( x(x - 10) = 0 \). Thus, the critical numbers are \( x = 0 \) and \( x = 10 \). Now, let's assess the behavior of \( f(x) \) around these points to find the intervals of increase. Test the intervals: 1. Choose \( x < 0 \) (e.g., \( x = -1 \)), \( f'(-1) > 0 \) (increasing). 2. Choose \( 0 < x < 5 \) (e.g., \( x = 1 \)), \( f'(1) < 0 \) (decreasing). 3. Choose \( 5 < x < 10 \) (e.g., \( x = 6 \)), \( f'(6) > 0 \) (increasing). 4. Choose \( x > 10 \) (e.g., \( x = 11 \)), \( f'(11) < 0 \) (decreasing). Thus, the function \( f(x) \) is increasing on the intervals \( (-\infty, 0) \) and \( (5, 10) \). A. The critical number(s) of the function are \( x=0, 10 \). A. The function is increasing on \( (-\infty, 0) \) and \( (5, 10) \).

Related Questions

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