Math Problem Statement

Find the limits in the following exercises: 17. lim (1 / (x^2 - 4)) as x approaches 2 and -2 from both left and right. 18. lim (x / (x^2 - 1)) as x approaches 1 from both left and right. 19. lim ((x^2 / 2) - (1 / x)) as x approaches 0 and other values. 20. lim ((x^2 / 2x + 4)) as x approaches -2 and 1 from both sides.

Solution

Let's solve the given problems by evaluating the limits as specified.

17. limx21x24\lim_{{x \to 2}} \frac{1}{{x^2 - 4}}

The function is 1x24\frac{1}{{x^2 - 4}}, which can be rewritten as 1(x2)(x+2)\frac{1}{{(x-2)(x+2)}}.

As x2+x \to 2^+:

  • As xx approaches 2 from the right, (x2)(x-2) is positive but close to zero, and (x+2)(x+2) is positive. Therefore, 1(x2)(x+2)\frac{1}{(x-2)(x+2)} approaches ++\infty.

As x2x \to 2^-:

  • As xx approaches 2 from the left, (x2)(x-2) is negative but close to zero, and (x+2)(x+2) is positive. Therefore, 1(x2)(x+2)\frac{1}{(x-2)(x+2)} approaches -\infty.

As x2+x \to -2^+:

  • As xx approaches 2-2 from the right, (x+2)(x+2) is positive but close to zero, and (x2)(x-2) is negative. Therefore, 1(x2)(x+2)\frac{1}{(x-2)(x+2)} approaches -\infty.

As x2x \to -2^-:

  • As xx approaches 2-2 from the left, (x+2)(x+2) is negative and close to zero, and (x2)(x-2) is negative. Therefore, (\

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Math Problem Analysis

Mathematical Concepts

Limits
Rational Functions
Asymptotes
Continuity

Formulas

lim (1 / (x^2 - 4))
lim (x / (x^2 - 1))
lim ((x^2 / 2) - (1 / x))

Theorems

Limit Laws
Indeterminate Forms
Asymptotic Behavior

Suitable Grade Level

Grades 11-12