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Ch. 8 - Techniques of Integration
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077Non è quello che usi tu?Cambia libro di testo
Capitolo 8, Problema 8.3.14

Evaluate the integrals in Exercises 1–22.
∫₀^(π/2) sin²(x) dx

Guida verificata passo dopo passo
1
Recognize that the integral involves the square of the sine function: \(\int_0^{\frac{\pi}{2}} \sin^2(x) \, dx\).
Use the power-reduction identity to rewrite \(\sin^2(x)\) in a more integrable form: \(\sin^2(x) = \frac{1 - \cos(2x)}{2}\).
Substitute this identity into the integral to get \(\int_0^{\frac{\pi}{2}} \frac{1 - \cos(2x)}{2} \, dx\).
Split the integral into two separate integrals: \(\frac{1}{2} \int_0^{\frac{\pi}{2}} 1 \, dx - \frac{1}{2} \int_0^{\frac{\pi}{2}} \cos(2x) \, dx\).
Evaluate each integral separately using basic integration rules, then combine the results to express the value of the original integral.

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Definite Integral

A definite integral calculates the net area under a curve between two specified limits. It is represented as ∫_a^b f(x) dx, where a and b are the lower and upper bounds. Evaluating a definite integral involves finding the antiderivative and then applying the Fundamental Theorem of Calculus.
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Definition of the Definite Integral

Trigonometric Identities

Trigonometric identities are equations involving trigonometric functions that hold true for all values in their domains. For integrals like ∫ sin²(x) dx, using identities such as the power-reduction formula sin²(x) = (1 - cos(2x))/2 simplifies the integral into a more manageable form.
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Fundamental Theorem of Calculus

This theorem links differentiation and integration, stating that if F is an antiderivative of f on [a, b], then ∫_a^b f(x) dx = F(b) - F(a). It allows evaluation of definite integrals by finding antiderivatives and computing their difference at the bounds.
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Fundamental Theorem of Calculus Part 1