Difference between revisions of "009A Sample Final 1, Problem 6"

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<span class="exam"> Consider the following function:
 
<span class="exam"> Consider the following function:
  
::::::<math>f(x)=3x-2\sin x+7</math>
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::<math>f(x)=3x-2\sin x+7</math>
  
<span class="exam">a) Use the Intermediate Value Theorem to show that <math>f(x)</math> has at least one zero.
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<span class="exam">(a) Use the Intermediate Value Theorem to show that &nbsp;<math style="vertical-align: -5px">f(x)</math>&nbsp; has at least one zero.
  
<span class="exam">b) Use the Mean Value Theorem to show that <math>f(x)</math> has at most one zero.
+
<span class="exam">(b) Use the Mean Value Theorem to show that &nbsp;<math style="vertical-align: -5px">f(x)</math>&nbsp; has at most one zero.
  
{| class="mw-collapsible mw-collapsed" style = "text-align:left;"
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<hr>
!Foundations: &nbsp;
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[[009A Sample Final 1, Problem 6 Solution|'''<u>Solution</u>''']]
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|
 
|}
 
  
'''Solution:'''
 
  
'''(a)'''
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[[009A Sample Final 1, Problem 6 Detailed Solution|'''<u>Detailed Solution</u>''']]
  
{| class="mw-collapsible mw-collapsed" style = "text-align:left;"
 
!Step 1: &nbsp;
 
|-
 
|First note that <math>f(0)=7</math>.
 
|-
 
|Also, <math>f(-5)=-15-2\sin(-5)+7=-8-2\sin(-5)</math>.
 
|-
 
|Since <math>-1\leq \sin(x) \leq 1</math>,
 
|-
 
|<math>-2\leq -2\sin(x) \leq 2</math>.
 
|-
 
|Thus, <math>-10\leq f(-5) \leq -6</math> and hence <math>f(-5)<0</math>.
 
|}
 
  
{| class="mw-collapsible mw-collapsed" style = "text-align:left;"
 
!Step 2: &nbsp;
 
|-
 
|Since <math>f(-5)<0</math> and <math>f(0)>0</math>, there exists <math>x</math> with <math>-5<x<0</math> such that
 
|-
 
|<math>f(x)=0</math> by the Intermediate Value Theorem. Hence, <math>f(x)</math> has at least one zero.
 
|}
 
 
'''(b)'''
 
 
{| class="mw-collapsible mw-collapsed" style = "text-align:left;"
 
!Step 1: &nbsp;
 
|-
 
|
 
|-
 
|
 
|-
 
|
 
|}
 
 
{| class="mw-collapsible mw-collapsed" style = "text-align:left;"
 
!Step 2: &nbsp;
 
|-
 
|
 
|}
 
 
{| class="mw-collapsible mw-collapsed" style = "text-align:left;"
 
!Step 3: &nbsp;
 
|-
 
|
 
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|}
 
 
{| class="mw-collapsible mw-collapsed" style = "text-align:left;"
 
!Final Answer: &nbsp;
 
|-
 
|'''(a)''' Since <math>f(-5)<0</math> and <math>f(0)>0</math>, there exists <math>x</math> with <math>-5<x<0</math> such that
 
|-
 
|<math>f(x)=0</math> by the Intermediate Value Theorem. Hence, <math>f(x)</math> has at least one zero.
 
|-
 
|'''(b)'''
 
|}
 
 
[[009A_Sample_Final_1|'''<u>Return to Sample Exam</u>''']]
 
[[009A_Sample_Final_1|'''<u>Return to Sample Exam</u>''']]

Latest revision as of 15:53, 2 December 2017

Consider the following function:

Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle f(x)=3x-2\sin x+7}

(a) Use the Intermediate Value Theorem to show that  Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle f(x)}   has at least one zero.

(b) Use the Mean Value Theorem to show that  Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle f(x)}   has at most one zero.


Solution


Detailed Solution


Return to Sample Exam