An area function Consider the functions y = x²/a and y = √x/a, where a>0. Find A(a), the area of the region between the curves.
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
9. Graphical Applications of Integrals
Area Between Curves
Problem 8.R.106
Textbook Question
106. Arc length Find the length of the curve y = (x / 2) * sqrt(3 - x^2) + (3 / 2) * sin^(-1)(x / sqrt(3)) from x = 0 to x = 1.
Verified step by step guidance1
Identify the formula for the arc length of a curve defined by a function \( y = f(x) \) from \( x = a \) to \( x = b \):
\[
L = \int_a^b \sqrt{1 + \left(\frac{dy}{dx}\right)^2} \, dx
\]
Given the function:
\[
y = \frac{x}{2} \sqrt{3 - x^2} + \frac{3}{2} \sin^{-1}\left(\frac{x}{\sqrt{3}}\right)
\]
we need to find its derivative \( \frac{dy}{dx} \). Use the product rule and chain rule for the first term, and the derivative of the inverse sine function for the second term.
Compute \( \frac{dy}{dx} \) step-by-step:
- For the first term \( \frac{x}{2} \sqrt{3 - x^2} \), write it as \( \frac{x}{2} (3 - x^2)^{1/2} \) and apply the product rule:
\[
\frac{d}{dx} \left( \frac{x}{2} (3 - x^2)^{1/2} \right) = \frac{1}{2} (3 - x^2)^{1/2} + \frac{x}{2} \cdot \frac{d}{dx} (3 - x^2)^{1/2}
\]
- For the derivative of \( (3 - x^2)^{1/2} \), use the chain rule:
\[
\frac{d}{dx} (3 - x^2)^{1/2} = \frac{1}{2} (3 - x^2)^{-1/2} \cdot (-2x) = -\frac{x}{(3 - x^2)^{1/2}}
\]
- For the second term \( \frac{3}{2} \sin^{-1}\left(\frac{x}{\sqrt{3}}\right) \), use the derivative of \( \sin^{-1}(u) \):
\[
\frac{d}{dx} \sin^{-1}(u) = \frac{1}{\sqrt{1 - u^2}} \cdot \frac{du}{dx}
\]
where \( u = \frac{x}{\sqrt{3}} \), so \( \frac{du}{dx} = \frac{1}{\sqrt{3}} \).
After finding \( \frac{dy}{dx} \), square it to get \( \left(\frac{dy}{dx}\right)^2 \). Then, substitute into the arc length integral formula:
\[
L = \int_0^1 \sqrt{1 + \left(\frac{dy}{dx}\right)^2} \, dx
\]
Set up the integral with the expression inside the square root simplified as much as possible. Finally, evaluate the integral either by analytical methods if possible or by numerical approximation to find the length of the curve from \( x = 0 \) to \( x = 1 \).
Verified video answer for a similar problem:This video solution was recommended by our tutors as helpful for the problem above
Video duration:
6mPlay a video:
Was this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Arc Length Formula
The arc length of a curve y = f(x) from x = a to x = b is found using the integral L = ∫_a^b √(1 + (dy/dx)^2) dx. This formula calculates the length by summing infinitesimal line segments along the curve, requiring the derivative of the function.
Recommended video:
Arc Length of Parametric Curves
Derivative of Composite and Inverse Functions
To find dy/dx for the given function, one must differentiate terms involving products, square roots, and inverse sine functions. Understanding the chain rule and derivatives of inverse trigonometric functions like sin^(-1)(x) is essential.
Recommended video:
Derivatives of Other Inverse Trigonometric Functions
Integration Techniques
After finding the integrand √(1 + (dy/dx)^2), evaluating the integral may require substitution or recognizing standard integral forms. Proficiency in integration methods helps in simplifying and computing the definite integral for arc length.
Recommended video:
Integration by Parts for Definite Integrals
Watch next
Master Finding Area Between Curves on a Given Interval with a bite sized video explanation from Patrick
Start learningRelated Videos
Related Practice
Textbook Question
12
views
