Math Problem Statement

Find the functions f + g, f - g, fg, and f/g. Given f(x) = 1 / (x^2 + 10) and g(x) = 1 / (x^2 - 10).

Solution

The image contains functions f(x)=1x2+10f(x) = \frac{1}{x^2 + 10} and g(x)=1x210g(x) = \frac{1}{x^2 - 10}, and it asks to find the following:

  1. f+gf + g
  2. fgf - g
  3. fgfg
  4. fg\frac{f}{g}

Let's work through these step by step.

1. f+gf + g:

f(x)+g(x)=1x2+10+1x210f(x) + g(x) = \frac{1}{x^2 + 10} + \frac{1}{x^2 - 10} To add these fractions, we need a common denominator: f(x)+g(x)=(x210)+(x2+10)(x2+10)(x210)=2x2(x4100)f(x) + g(x) = \frac{(x^2 - 10) + (x^2 + 10)}{(x^2 + 10)(x^2 - 10)} = \frac{2x^2}{(x^4 - 100)} Thus, f(x)+g(x)=2x2x4100f(x) + g(x) = \frac{2x^2}{x^4 - 100}

2. fgf - g:

f(x)g(x)=1x2+101x210f(x) - g(x) = \frac{1}{x^2 + 10} - \frac{1}{x^2 - 10} Using the common denominator as before: f(x)g(x)=(x210)(x2+10)(x2+10)(x210)=20x4100f(x) - g(x) = \frac{(x^2 - 10) - (x^2 + 10)}{(x^2 + 10)(x^2 - 10)} = \frac{-20}{x^4 - 100} Thus, f(x)g(x)=20x4100f(x) - g(x) = \frac{-20}{x^4 - 100}

3. fgfg:

fg=1x2+10×1x210=1(x2+10)(x210)fg = \frac{1}{x^2 + 10} \times \frac{1}{x^2 - 10} = \frac{1}{(x^2 + 10)(x^2 - 10)} Since (x2+10)(x210)=x4100(x^2 + 10)(x^2 - 10) = x^4 - 100, we have: fg=1x4100fg = \frac{1}{x^4 - 100}

4. fg\frac{f}{g}:

f(x)g(x)=1x2+101x210=x210x2+10\frac{f(x)}{g(x)} = \frac{\frac{1}{x^2 + 10}}{\frac{1}{x^2 - 10}} = \frac{x^2 - 10}{x^2 + 10} Thus, fg=x210x2+10\frac{f}{g} = \frac{x^2 - 10}{x^2 + 10}

Would you like further details on any of the steps?

Here are five related questions to expand your understanding:

  1. How would the results change if f(x)f(x) and g(x)g(x) had different powers of xx?
  2. Can you factor x4100x^4 - 100 into simpler components?
  3. What happens if x2=10x^2 = 10? Are there any restrictions on xx?
  4. How do these operations affect the domains of ff and gg?
  5. Can you graph these combined functions and interpret their intersections?

Tip: Always check for any restrictions in the domain when performing operations with functions. For instance, ensure that denominators are not zero!

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Math Problem Analysis

Mathematical Concepts

Algebra
Function Operations
Rational Functions

Formulas

f + g = 1 / (x^2 + 10) + 1 / (x^2 - 10)
f - g = 1 / (x^2 + 10) - 1 / (x^2 - 10)
fg = (1 / (x^2 + 10)) * (1 / (x^2 - 10))
f / g = (1 / (x^2 + 10)) / (1 / (x^2 - 10))

Theorems

Common Denominator Theorem for Adding/Subtracting Fractions

Suitable Grade Level

Grades 9-12