Chapter 4: Problem 39
In Exercises \(37-40 :\)
a. Find the local extrema of each function on the given interval, and say
where they are assumed.
b. Graph the function and its derivative together. Comment on the behavior of
\(f\) in relation to the signs and values of \(f^{\prime} .\)
$$
f(x)=\csc ^{2} x-2 \cot x, \quad 0
Short Answer
Step by step solution
Find the derivative of the function
Set the derivative equal to zero to find critical points
Evaluate the function at critical points and endpoints
Graph the function and derivative
Analyze the behavior of the function in relation to its derivative
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Trigonometric Functions
These functions are the reciprocals of the sine and tangent functions, respectively.
- The cosecant function is expressed as \({\csc x = \frac{1}{\sin x}}\).
- The cotangent is expressed as \({\cot x = \frac{1}{\tan x}} = \frac{\cos x}{\sin x}\).
Critical Points
For trigonometric functions, careful consideration is needed as points where functions like \( \csc x \) or \( \cot x \) are undefined may also impact outcomes. In this exercise, solving \( \cot x + \csc x = 0 \) leads to identifying points on the function's behavior within the interval \( (0, \pi) \). At these points, the function performs notable transitions that need further exploration visually or analytically.
Graphical Analysis
This visualization supports identifying local extrema and understanding changes in the function's slope.
- Plot \( f(x) = \csc^2 x - 2 \cot x \).
- Plot its derivative \( f'(x) = 2 \csc x \cot x + 2 \csc^2 x \).
Derivative Calculation
For the function \( f(x) = \csc^2 x - 2 \cot x \), the derivative is calculated using known derivatives of trigonometric functions:
- The derivative of \( \csc x \) is \( -\csc x \cot x \).
- The derivative of \( \cot x \) is \( -\csc^2 x \).