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
4. Applications of Derivatives
Related Rates
Problem 3.11.8
Textbook Question
At all times, the length of the long leg of a right triangle is 3 times the length x of the short leg of the triangle. If the area of the triangle changes with respect to time t, find equations relating the area A to x and dA/dt to dx/dt.
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1
Start by expressing the relationship between the lengths of the legs of the triangle. Let the length of the short leg be x, then the long leg is 3x.
Use the formula for the area A of a right triangle, which is A = (1/2) * base * height. Here, base = x and height = 3x, so A = (1/2) * x * (3x).
Simplify the area formula to find A in terms of x: A = (3/2) * x^2.
Differentiate the area A with respect to time t using the chain rule: dA/dt = dA/dx * dx/dt, where dA/dx is the derivative of A with respect to x.
Calculate dA/dx from the area formula A = (3/2) * x^2, which gives dA/dx = 3x, and substitute this into the equation to relate dA/dt to dx/dt.
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