Table of contents
- 0. Functions7h 52m
- Introduction to Functions16m
- Piecewise Functions10m
- Properties of Functions9m
- Common Functions1h 8m
- Transformations5m
- Combining Functions27m
- Exponent rules32m
- Exponential Functions28m
- Logarithmic Functions24m
- Properties of Logarithms34m
- Exponential & Logarithmic Equations35m
- Introduction to Trigonometric Functions38m
- Graphs of Trigonometric Functions44m
- Trigonometric Identities47m
- Inverse Trigonometric Functions48m
- 1. Limits and Continuity2h 2m
- 2. Intro to Derivatives1h 33m
- 3. Techniques of Differentiation3h 18m
- 4. Applications of Derivatives2h 38m
- 5. Graphical Applications of Derivatives6h 2m
- 6. Derivatives of Inverse, Exponential, & Logarithmic Functions2h 37m
- 7. Antiderivatives & Indefinite Integrals1h 26m
1. Limits and Continuity
Finding Limits Algebraically
Problem 72a
Textbook Question
Analyze lim x→∞ f(x) and lim x→−∞ f(x), and then identify any horizontal asymptotes.
f(x) = (√(16x4 + 64x2) + x2) / (2x2 − 4)
![](/channels/images/assetPage/verifiedSolution.png)
1
Step 1: Simplify the expression inside the square root. Notice that the dominant term inside the square root as x approaches infinity is 16x^4. Factor out x^4 from the square root: \( \sqrt{16x^4 + 64x^2} = x^2\sqrt{16 + \frac{64}{x^2}} \).
Step 2: Simplify the expression for f(x) by dividing the numerator and the denominator by x^2, the highest power of x in the denominator: \( f(x) = \frac{x^2\sqrt{16 + \frac{64}{x^2}} + x^2}{2x^2 - 4} = \frac{x^2(\sqrt{16 + \frac{64}{x^2}} + 1)}{2x^2 - 4} \).
Step 3: Evaluate the limit as x approaches infinity. As x approaches infinity, \( \frac{64}{x^2} \) approaches 0, so \( \sqrt{16 + \frac{64}{x^2}} \) approaches \( \sqrt{16} = 4 \). Therefore, the expression simplifies to \( \frac{x^2(4 + 1)}{2x^2 - 4} = \frac{5x^2}{2x^2 - 4} \).
Step 4: Simplify the expression \( \frac{5x^2}{2x^2 - 4} \) by dividing the numerator and the denominator by x^2: \( \frac{5}{2 - \frac{4}{x^2}} \). As x approaches infinity, \( \frac{4}{x^2} \) approaches 0, so the expression approaches \( \frac{5}{2} \).
Step 5: Evaluate the limit as x approaches negative infinity. The process is similar to the positive infinity case, and the expression \( \frac{5}{2 - \frac{4}{x^2}} \) also approaches \( \frac{5}{2} \). Therefore, the horizontal asymptote is y = \frac{5}{2}.
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