NOTE: When using interval notation in WeBWork, remember that: You use 'INF' for o and '-INF' for -o. And use 'U' for the union symbol. Enter DNE if an answer does not exist. f(x) = 5 sin x +4 cos x, on (- π, π) a) Determine the intervals on which f is concave up and concave down.

Calculus: Early Transcendentals
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ISBN:9781285741550
Author:James Stewart
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Chapter1: Functions And Models
Section: Chapter Questions
Problem 1RCC: (a) What is a function? What are its domain and range? (b) What is the graph of a function? (c) How...
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NEED HELP WITH CALCULUS. I TRIED THIS N GOT IT WRONG. PLEASE DONT USE "TAN" WORD IN YOUR ANSWER. WRITE THE ANS IN TERMS OF "PI". AND DONT MAKE IT TOO COMPLEX. 

### Calculus: Analyzing Concavity and Extrema

#### Problem Statement

Given the function \( f(x) = 5 \sin x + 4 \cos x \), defined on the interval \((-π, π)\):

### Part (a): Determine the Intervals of Concavity

1. **Concave Up:**

   \( f \) is concave up on: 
   \[
   \left( -\pi, -\tan^{-1}\left(\frac{40}{9}/2\right) \right) \cup \left( \pi (-\tan^{-1}\left(\frac{40}{9}/2\right) \right)
   \]

2. **Concave Down:**
   
   \( f \) is concave down on:
   \[
   (-\pi, 2.4669)
   \]

### Part (b): Inflection Points

Based on the answer to part (a), the inflection points of \( f \) are:

\[
(2.4669, 0)
\]

*Note: Enter multiple answers separated by commas.*

### Part (c): Critical Numbers and Relative Extrema

Find the critical numbers of \( f \) and use the Second Derivative Test to determine the relative extrema.

1. **Relative Maxima:**
   
   Relative maxima occur at:
   \[
   0.897
   \]

2. **Relative Minima:**

   Relative minima occur at:
   \[
   \text{dne}
   \]

### Part (d): \( x \)-Values for Relative Maxima or Minima of \( f' \)

Determine the \( x \)-values where \( f'(x) \) has a relative maximum or minimum.

1. **Relative Maxima of \( f' \):**
   
   \( f' \) has a relative maximum at:
   \[
   (2.4669)
   \]

2. **Relative Minima of \( f' \):**
   
   \( f' \) has a relative minimum at:
   \[
   0
   \]

*Note: Enter multiple answers separated by commas.*

This exercise helps in understanding the concavity, inflection points, and relative extrema of trigonometric functions using calculus concepts such as the second derivative test.
Transcribed Image Text:### Calculus: Analyzing Concavity and Extrema #### Problem Statement Given the function \( f(x) = 5 \sin x + 4 \cos x \), defined on the interval \((-π, π)\): ### Part (a): Determine the Intervals of Concavity 1. **Concave Up:** \( f \) is concave up on: \[ \left( -\pi, -\tan^{-1}\left(\frac{40}{9}/2\right) \right) \cup \left( \pi (-\tan^{-1}\left(\frac{40}{9}/2\right) \right) \] 2. **Concave Down:** \( f \) is concave down on: \[ (-\pi, 2.4669) \] ### Part (b): Inflection Points Based on the answer to part (a), the inflection points of \( f \) are: \[ (2.4669, 0) \] *Note: Enter multiple answers separated by commas.* ### Part (c): Critical Numbers and Relative Extrema Find the critical numbers of \( f \) and use the Second Derivative Test to determine the relative extrema. 1. **Relative Maxima:** Relative maxima occur at: \[ 0.897 \] 2. **Relative Minima:** Relative minima occur at: \[ \text{dne} \] ### Part (d): \( x \)-Values for Relative Maxima or Minima of \( f' \) Determine the \( x \)-values where \( f'(x) \) has a relative maximum or minimum. 1. **Relative Maxima of \( f' \):** \( f' \) has a relative maximum at: \[ (2.4669) \] 2. **Relative Minima of \( f' \):** \( f' \) has a relative minimum at: \[ 0 \] *Note: Enter multiple answers separated by commas.* This exercise helps in understanding the concavity, inflection points, and relative extrema of trigonometric functions using calculus concepts such as the second derivative test.
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