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Ch. 10 - Infinite Sequences and Series
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077Non è quello che usi tu?Cambia libro di testo
Capitolo 10, Problema 10.8.41a

Quadratic Approximations The Taylor polynomial of order 2 generated by a twice-differentiable function f(x) at x = a is called the quadratic approximation of f at x = a. In Exercises 41–46, find the (a) linearization (Taylor polynomial of order 1)
f(x) = ln(cos x)

Guida verificata passo dopo passo
1
Identify the point at which the Taylor polynomial is to be generated, denoted as \(a\). This is the center of the approximation.
Recall that the linearization (Taylor polynomial of order 1) of a function \(f(x)\) at \(x = a\) is given by the formula: \[L(x) = f(a) + f'(a)(x - a)\]
Calculate the value of the function at \(x = a\): \[f(a) = \ln(\cos a)\]
Find the first derivative of the function \(f(x) = \ln(\cos x)\). Use the chain rule: \[f'(x) = \frac{d}{dx} \ln(\cos x) = \frac{1}{\cos x} \cdot (-\sin x) = -\tan x\]
Evaluate the first derivative at \(x = a\): \[f'(a) = -\tan a\] Then substitute \(f(a)\) and \(f'(a)\) into the linearization formula to write the linear approximation.

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