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
Differentials
Problem 4.6.62
Textbook Question
Differentials Consider the following functions and express the relationship between a small change in x and the corresponding change in y in the form dy = f'(x)dx.
f(x) = sin² x
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1
Identify the function f(x) = sin²(x) and recognize that we need to find its derivative f'(x).
Use the chain rule to differentiate f(x). Recall that if f(x) = g(h(x)), then f'(x) = g'(h(x)) * h'(x). Here, g(u) = u² and h(x) = sin(x).
Calculate the derivative of g(u) = u², which is g'(u) = 2u, and the derivative of h(x) = sin(x), which is h'(x) = cos(x).
Substitute h(x) back into g'(u) to find f'(x) = 2sin(x) * cos(x). This can also be expressed as f'(x) = sin(2x) using the double angle identity.
Express the relationship between the small change in x (dx) and the corresponding change in y (dy) using the formula dy = f'(x)dx, substituting the expression for f'(x) found in the previous step.
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