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Ch. 4 - Applications of Derivatives
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077Non è quello che usi tu?Cambia libro di testo
Capitolo 4, Problema 4.7.66a

Checking Antiderivative Formulas


Right, or wrong? Say which for each formula and give a brief reason for each answer.


∫√(2x + 1) dx = √(x² + x +C)

Guida verificata passo dopo passo
1
Identify the integral to be checked: \(\int \sqrt{2x + 1} \, dx\) and the proposed antiderivative \(\sqrt{x^2 + x + C}\).
Recall that to verify if a function \(F(x)\) is an antiderivative of \(f(x)\), we differentiate \(F(x)\) and check if \(F'(x) = f(x)\).
Differentiate the proposed antiderivative \(F(x) = \sqrt{x^2 + x + C}\) using the chain rule: \(F'(x) = \frac{1}{2\sqrt{x^2 + x + C}} \cdot (2x + 1)\).
Compare \(F'(x)\) with the original integrand \(\sqrt{2x + 1}\). Notice that \(F'(x)\) has a denominator involving \(\sqrt{x^2 + x + C}\), which is not present in the original integrand.
Conclude that since \(F'(x) \neq \sqrt{2x + 1}\), the proposed antiderivative is incorrect.

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