Difference between revisions of "009A Sample Midterm 2, Problem 2"

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<span class="exam">The function <math>f(x)=3x^7-8x+2</math> is a polynomial and therefore continuous everywhere.
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<span class="exam">The function &nbsp;<math style="vertical-align: -5px">f(x)=3x^7-8x+2</math>&nbsp; is a polynomial and therefore continuous everywhere.
::<span class="exam">a) State the Intermediate Value Theorem.
 
::<span class="exam">b) Use the Intermediate Value Theorem to show that <math>f(x)</math> has a zero in the interval <math>[0,1].</math>
 
  
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<span class="exam">(a) State the Intermediate Value Theorem.
  
{| class="mw-collapsible mw-collapsed" style = "text-align:left;"
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<span class="exam">(b) Use the Intermediate Value Theorem to show that &nbsp;<math style="vertical-align: -5px">f(x)</math>&nbsp; has a zero in the interval &nbsp;<math style="vertical-align: -5px">[0,1].</math>
!Foundations: &nbsp;  
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<hr>
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[[009A Sample Midterm 2, Problem 2 Solution|'''<u>Solution</u>''']]
|?
 
|}
 
  
  
'''Solution:'''
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[[009A Sample Midterm 2, Problem 2 Detailed Solution|'''<u>Detailed Solution</u>''']]
  
'''(a)'''
 
{| class="mw-collapsible mw-collapsed" style = "text-align:left;"
 
!Step 1: &nbsp;
 
|-
 
|'''Intermediate Value Theorem'''
 
|-
 
|&nbsp; &nbsp; &nbsp; &nbsp; If <math style="vertical-align: -5px">f(x)</math>&thinsp; is continuous on a closed interval <math style="vertical-align: -5px">[a,b]</math>
 
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|&nbsp; &nbsp; &nbsp; &nbsp; and <math style="vertical-align: 0px">c</math> is any number between <math style="vertical-align: -5px">f(a)</math>&thinsp; and <math style="vertical-align: -5px">f(b)</math>,
 
|-
 
|
 
&nbsp; &nbsp; &nbsp; &nbsp; then there is at least one number <math style="vertical-align: 0px">x</math> in the closed interval such that <math style="vertical-align: -5px">f(x)=c.</math>
 
|}
 
  
'''(b)'''
 
{| class="mw-collapsible mw-collapsed" style = "text-align:left;"
 
!Step 1: &nbsp;
 
|-
 
|First, <math>f(x)</math> is continuous on the interval <math>[0,1]</math> since <math>f(x)</math> is continuous everywhere.
 
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|Also,
 
|-
 
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&nbsp; &nbsp; &nbsp; &nbsp; <math>f(0)=2</math>
 
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|and
 
&nbsp; &nbsp; &nbsp; &nbsp; <math>f(1)=3-8+2=-3.</math>.
 
|}
 
 
{| class="mw-collapsible mw-collapsed" style = "text-align:left;"
 
!Step 2: &nbsp;
 
|-
 
|Since <math>0</math> is between <math>f(0)=2</math> and <math>f(1)=-3,</math>
 
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|the Intermediate Value Theorem tells us that there is at least one number <math>x</math>
 
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|such that <math>f(x)=0.</math>
 
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|This means that <math>f(x)</math> has a zero in the interval <math>[0,1].</math>
 
|}
 
 
 
{| class="mw-collapsible mw-collapsed" style = "text-align:left;"
 
!Final Answer: &nbsp;
 
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|&nbsp; &nbsp; '''(a)''' &nbsp; &nbsp; See solution above.
 
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|&nbsp; &nbsp; '''(b)''' &nbsp; &nbsp; See solution above.
 
|}
 
 
[[009A_Sample_Midterm_2|'''<u>Return to Sample Exam</u>''']]
 
[[009A_Sample_Midterm_2|'''<u>Return to Sample Exam</u>''']]

Latest revision as of 15:35, 9 November 2017

The function    is a polynomial and therefore continuous everywhere.

(a) State the Intermediate Value Theorem.

(b) Use the Intermediate Value Theorem to show that    has a zero in the interval  


Solution


Detailed Solution


Return to Sample Exam