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Ch. 4 - Applications of Derivatives
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077Not the one you use?Change textbook
Chapter 4, Problem 4.7.51

Finding Indefinite Integrals


In Exercises 17–56, find the most general antiderivative or indefinite integral. You may need to try a solution and then adjust your guess. Check your answers by differentiation.


∫(1 + tan²θ)dθ (Hint:1 + tan²θ = sec²θ)

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1
Recognize the integral given: \(\int (1 + \tan^{2}\theta) \, d\theta\).
Use the hint provided, which states that \(1 + \tan^{2}\theta = \sec^{2}\theta\). Substitute this into the integral to simplify it to \(\int \sec^{2}\theta \, d\theta\).
Recall the basic integral formula: \(\int \sec^{2}x \, dx = \tan x + C\), where \(C\) is the constant of integration.
Apply this formula to the integral, replacing \(x\) with \(\theta\), so the antiderivative is \(\tan \theta + C\).
Verify your result by differentiating \(\tan \theta + C\) to check if it returns the original integrand \(1 + \tan^{2}\theta\).

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Key Concepts

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

Indefinite Integral

An indefinite integral represents the most general antiderivative of a function, including a constant of integration. It is written without limits and describes a family of functions whose derivative is the integrand.
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Trigonometric Identities

Trigonometric identities are equations involving trigonometric functions that hold true for all values in their domains. For example, the identity 1 + tan²θ = sec²θ simplifies integrals by rewriting expressions into more manageable forms.
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Verification by Differentiation

After finding an antiderivative, differentiating it should return the original integrand. This step confirms the correctness of the indefinite integral and ensures no errors were made during integration.
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