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
2. Intro to Derivatives
Derivatives as Functions
6:03 minutes
Problem 3.1.58
Textbook Question
Find the function The following limits represent the slope of a curve y = f(x) at the point (a,f(a)). Determine a possible function f and number a; then calculate the limit.
(lim x🠂2) 1/x+1 - 1/3 / x-2
Verified step by step guidance
1
Step 1: Recognize that the given limit represents the derivative of a function at a point. The expression \( \lim_{{x \to 2}} \frac{\frac{1}{x+1} - \frac{1}{3}}{x-2} \) is in the form of the definition of the derivative \( f'(a) = \lim_{{x \to a}} \frac{f(x) - f(a)}{x-a} \).
Step 2: Identify the function \( f(x) \) and the point \( a \). From the expression \( \frac{1}{x+1} \), we can deduce that \( f(x) = \frac{1}{x+1} \). The point \( a \) is given by the limit \( x \to 2 \), so \( a = 2 \).
Step 3: Calculate \( f(a) \). Substitute \( a = 2 \) into \( f(x) \) to find \( f(2) = \frac{1}{2+1} = \frac{1}{3} \). This matches the \( \frac{1}{3} \) in the limit expression, confirming our function and point.
Step 4: Set up the derivative calculation. The derivative \( f'(x) \) is given by \( \lim_{{x \to 2}} \frac{f(x) - f(2)}{x-2} = \lim_{{x \to 2}} \frac{\frac{1}{x+1} - \frac{1}{3}}{x-2} \).
Step 5: Simplify the expression to find the limit. Combine the fractions in the numerator: \( \frac{1}{x+1} - \frac{1}{3} = \frac{3 - (x+1)}{3(x+1)} = \frac{2-x}{3(x+1)} \). Substitute this back into the limit: \( \lim_{{x \to 2}} \frac{\frac{2-x}{3(x+1)}}{x-2} \). Simplify and evaluate the limit.
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