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Ch. 8 - Techniques of Integration
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077Not the one you use?Change textbook
Chapter 8, Problem 8.2.50

Evaluate the integrals in Exercises 31–56. Some integrals do not require integration by parts.
∫₀¹/√2 2x arcsin(x²) dx

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Identify the integral to solve: \(\int_0^{\frac{1}{\sqrt{2}}} 2x \arcsin(x^2) \, dx\).
Recognize that the integrand is a product of two functions: \$2x$ and \(\arcsin(x^2)\). This suggests using integration by parts, where one function is differentiated and the other is integrated.
Choose \(u = \arcsin(x^2)\), so that \(du = \frac{d}{dx} \arcsin(x^2) \, dx\). Use the chain rule to find \(du\): \(du = \frac{1}{\sqrt{1 - (x^2)^2}} \cdot 2x \, dx = \frac{2x}{\sqrt{1 - x^4}} \, dx\).
Let \(dv = 2x \, dx\), then integrate to find \(v\): \(v = \int 2x \, dx = x^2\).
Apply the integration by parts formula: \(\int u \, dv = uv - \int v \, du\). Substitute the expressions for \(u\), \(v\), and \(du\) to rewrite the integral and simplify before evaluating the definite integral from \(0\) to \(\frac{1}{\sqrt{2}}\).

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Integration by Parts

Integration by parts is a technique used to integrate products of functions. It is based on the product rule for differentiation and is given by ∫u dv = uv - ∫v du. Choosing u and dv wisely simplifies the integral, especially when one function becomes simpler upon differentiation.
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Inverse Trigonometric Functions

Inverse trigonometric functions, like arcsin(x), are the inverses of the standard trigonometric functions. Understanding their derivatives and integrals is essential, as arcsin(x) has a derivative of 1/√(1 - x²), which often appears in integration problems involving these functions.
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Definite Integrals and Limits of Integration

Definite integrals compute the net area under a curve between two limits. Evaluating a definite integral requires applying the Fundamental Theorem of Calculus after finding the antiderivative, then substituting the upper and lower limits to find the exact value.
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Definition of the Definite Integral