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
- 8. Definite Integrals3h 25m
5. Graphical Applications of Derivatives
The Second Derivative Test
Problem 4.3.85
Textbook Question
Second Derivative Test Locate the critical points of the following functions. Then use the Second Derivative Test to determine (if possible) whether they correspond to local maxima or local minima.
f(x) = x²e⁻ˣ
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1
First, find the first derivative of the function f(x) = x²e⁻ˣ using the product rule, which states that if you have two functions u(x) and v(x), then the derivative is u'v + uv'.
Set the first derivative equal to zero to locate the critical points. This involves solving the equation f'(x) = 0.
Next, find the second derivative of the function f(x) to apply the Second Derivative Test. This may involve differentiating the first derivative you found in the previous step.
Evaluate the second derivative at each critical point found in step 2. This will help determine the concavity of the function at those points.
Finally, apply the Second Derivative Test: if f''(x) > 0 at a critical point, it is a local minimum; if f''(x) < 0, it is a local maximum; if f''(x) = 0, the test is inconclusive.
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