Skip to main content
Ch. 7 - Transcendental Functions
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077Not the one you use?Change textbook
Chapter 7, Problem 7.PE.17

In Exercises 1–24, find the derivative of y with respect to the appropriate variable.
17. y = ln(arccos(x))

Verified step by step guidance
1
Identify the function given: \(y = \ln(\arccos(x))\). We need to find \(\frac{dy}{dx}\), the derivative of \(y\) with respect to \(x\).
Recall the chain rule for derivatives: if \(y = \ln(u)\), then \(\frac{dy}{dx} = \frac{1}{u} \cdot \frac{du}{dx}\). Here, \(u = \arccos(x)\).
Find the derivative of the inner function \(u = \arccos(x)\). The derivative is \(\frac{du}{dx} = -\frac{1}{\sqrt{1 - x^2}}\).
Apply the chain rule by substituting \(u\) and \(\frac{du}{dx}\) into the formula: \(\frac{dy}{dx} = \frac{1}{\arccos(x)} \cdot \left(-\frac{1}{\sqrt{1 - x^2}}\right)\).
Simplify the expression to write the derivative as \(\frac{dy}{dx} = -\frac{1}{\arccos(x) \sqrt{1 - x^2}}\).

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
2m
Was this helpful?

Key Concepts

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

Chain Rule

The chain rule is a fundamental differentiation technique used to find the derivative of composite functions. It states that the derivative of f(g(x)) is f'(g(x)) multiplied by g'(x). In this problem, since y = ln(arccos(x)) is a composition of ln(u) and u = arccos(x), the chain rule is essential.
Recommended video:
05:02
Intro to the Chain Rule

Derivative of the Natural Logarithm Function

The derivative of ln(u), where u is a differentiable function of x, is 1/u times the derivative of u. This rule helps differentiate logarithmic functions by simplifying the process to the derivative of the inner function divided by the original function.
Recommended video:
05:18
Derivative of the Natural Logarithmic Function

Derivative of the Arccosine Function

The derivative of arccos(x) with respect to x is -1 divided by the square root of (1 - x^2). This formula is crucial for differentiating inverse trigonometric functions and is needed to find the derivative of the inner function in the given problem.
Recommended video:
06:30
Derivatives of Other Trig Functions