(b) Find the average value of ƒ shown in the figure on the interval [2,6] and then find the point(s) c in (2, 6) guaranteed to exist by the Mean Value Theorem for Integrals.
Table of contents
- 0. Functions7h 54m
- Introduction to Functions16m
- Piecewise Functions10m
- Properties of Functions9m
- Common Functions1h 8m
- Transformations5m
- Combining Functions27m
- Exponent rules32m
- Exponential Functions28m
- Logarithmic Functions24m
- Properties of Logarithms36m
- 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 Integrals4h 44m
- 9. Graphical Applications of Integrals2h 27m
- 10. Physics Applications of Integrals 3h 16m
- 11. Integrals of Inverse, Exponential, & Logarithmic Functions2h 34m
- 12. Techniques of Integration7h 41m
- 13. Intro to Differential Equations2h 55m
- 14. Sequences & Series5h 36m
- 15. Power Series2h 19m
- 16. Parametric Equations & Polar Coordinates7h 58m
8. Definite Integrals
Introduction to Definite Integrals
Problem 6.1.72
Textbook Question
Without evaluating integrals, prove that ∫₀² d/dx(12 sin πx²) dx=∫₀² d/dx (x¹⁰(2−x)³) dx.
Verified step by step guidance1
Recognize that both integrals are definite integrals of derivatives over the interval from 0 to 2. According to the Fundamental Theorem of Calculus, for a function \(F(x)\), we have \(\int_a^b F'(x) \, dx = F(b) - F(a)\).
Apply the Fundamental Theorem of Calculus to the first integral: \(\int_0^2 \frac{d}{dx} \left(12 \sin \pi x^2 \right) \, dx = 12 \sin \pi (2)^2 - 12 \sin \pi (0)^2\).
Similarly, apply the Fundamental Theorem of Calculus to the second integral: \(\int_0^2 \frac{d}{dx} \left(x^{10} (2 - x)^3 \right) \, dx = (2)^{10} (2 - 2)^3 - (0)^{10} (2 - 0)^3\).
Evaluate the boundary terms in both expressions without simplifying the trigonometric or polynomial values, just observe their forms: For the first, \$12 \sin (4 \pi)\( and \)12 \sin 0\(; for the second, \)(2)^{10} \cdot 0^3\( and \)0^{10} \cdot 2^3$.
Note that \(\sin (4 \pi) = 0\) and \(\sin 0 = 0\), and that any term multiplied by zero is zero, so both expressions evaluate to zero, proving the equality of the two integrals without explicitly evaluating the integrals themselves.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Fundamental Theorem of Calculus
This theorem connects differentiation and integration, stating that the integral of a derivative over an interval equals the difference of the original function's values at the interval endpoints. It allows evaluating definite integrals of derivatives without performing integration.
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Properties of Definite Integrals
Definite integrals have linearity and additivity properties, and when integrating a derivative, the integral depends only on the boundary values of the original function. This means integrals of derivatives can be compared by evaluating the functions at the limits.
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Equality of Functions at Interval Endpoints
To prove two integrals of derivatives are equal without integration, it suffices to show the original functions have the same values at the interval's endpoints. If f(a) = g(a) and f(b) = g(b), then ∫ₐᵇ f'(x) dx = ∫ₐᵇ g'(x) dx.
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