Math Problem Statement

If 

f(x) = x3 − 10/x,

 find the following. (Give exact answers. Do not round.)

(a)    

f − 

1

2

 

(b)    

f(2)

 

(c)    

f(−2)

 

Solution

We are given the function f(x)=x310xf(x) = x^3 - \frac{10}{x}. Let's compute each of the requested values step by step.


(a) f(12)f\left(-\frac{1}{2}\right)

Substitute x=12x = -\frac{1}{2} into the function: f(12)=(12)31012f\left(-\frac{1}{2}\right) = \left(-\frac{1}{2}\right)^3 - \frac{10}{-\frac{1}{2}}

Step-by-step:

  1. (12)3=18\left(-\frac{1}{2}\right)^3 = -\frac{1}{8},
  2. 1012=102=20-\frac{10}{-\frac{1}{2}} = 10 \cdot 2 = 20,
  3. Combine the terms: 18+20=1+1608=1598-\frac{1}{8} + 20 = \frac{-1 + 160}{8} = \frac{159}{8}.

Thus, f(12)=1598f\left(-\frac{1}{2}\right) = \frac{159}{8}.


(b) f(2)f(2)

Substitute x=2x = 2 into the function: f(2)=23102f(2) = 2^3 - \frac{10}{2}

Step-by-step:

  1. 23=82^3 = 8,
  2. 102=5-\frac{10}{2} = -5,
  3. Combine the terms: 85=38 - 5 = 3.

Thus, f(2)=3f(2) = 3.


(c) f(2)f(-2)

Substitute x=2x = -2 into the function: f(2)=(2)3102f(-2) = (-2)^3 - \frac{10}{-2}

Step-by-step:

  1. (2)3=8(-2)^3 = -8,
  2. 102=5-\frac{10}{-2} = 5,
  3. Combine the terms: 8+5=3-8 + 5 = -3.

Thus, f(2)=3f(-2) = -3.


Final Answers:

(a) f(12)=1598f\left(-\frac{1}{2}\right) = \frac{159}{8}
(b) f(2)=3f(2) = 3
(c) f(2)=3f(-2) = -3


Would you like further details or clarification?
Here are 5 related questions to explore:

  1. How is the domain of f(x)f(x) affected by the term 10x\frac{10}{x}?
  2. What is the derivative f(x)f'(x) of this function?
  3. How would the function behave as xx \to \infty and x0x \to 0?
  4. What are the roots of f(x)f(x), if any?
  5. Can you determine the critical points of f(x)f(x)?

Tip: Always check for undefined points in rational functions where the denominator is zero!

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Math Problem Analysis

Mathematical Concepts

Algebra
Rational Functions
Function Evaluation

Formulas

f(x) = x^3 - 10/x

Theorems

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Suitable Grade Level

Grades 9-11