Average Value - Graphs












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$begingroup$


enter image description here



long method: Determine an equation for each and solve using average value formula



alternative methods?



How could you prove the average value to be C over an interval [a,b] if you are given a graph.... looking for most efficient/unique methods.










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  • $begingroup$
    In general you would integrate the function (to find the area below the curve) and divide by the length of the interval ($b-a=6$ here) but I think what is expected here is just to use a bit of guesswork: graph A clearly has an average $>2$, whereas by computing the area of triangles you can find that the average of C and D are 2 and 4 respectively. To show that B has $>2$, just draw the triangle {(0,0),(6,0),(3,4)} : it is contained in the area of the curve and has area =2
    $endgroup$
    – user157321
    Jul 30 '14 at 12:58
















0












$begingroup$


enter image description here



long method: Determine an equation for each and solve using average value formula



alternative methods?



How could you prove the average value to be C over an interval [a,b] if you are given a graph.... looking for most efficient/unique methods.










share|cite|improve this question











$endgroup$












  • $begingroup$
    In general you would integrate the function (to find the area below the curve) and divide by the length of the interval ($b-a=6$ here) but I think what is expected here is just to use a bit of guesswork: graph A clearly has an average $>2$, whereas by computing the area of triangles you can find that the average of C and D are 2 and 4 respectively. To show that B has $>2$, just draw the triangle {(0,0),(6,0),(3,4)} : it is contained in the area of the curve and has area =2
    $endgroup$
    – user157321
    Jul 30 '14 at 12:58














0












0








0





$begingroup$


enter image description here



long method: Determine an equation for each and solve using average value formula



alternative methods?



How could you prove the average value to be C over an interval [a,b] if you are given a graph.... looking for most efficient/unique methods.










share|cite|improve this question











$endgroup$




enter image description here



long method: Determine an equation for each and solve using average value formula



alternative methods?



How could you prove the average value to be C over an interval [a,b] if you are given a graph.... looking for most efficient/unique methods.







calculus integration algebra-precalculus definite-integrals






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share|cite|improve this question













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edited Jul 30 '14 at 12:57









apnorton

15.2k33796




15.2k33796










asked Jul 30 '14 at 12:48









confusedconfused

40821019




40821019












  • $begingroup$
    In general you would integrate the function (to find the area below the curve) and divide by the length of the interval ($b-a=6$ here) but I think what is expected here is just to use a bit of guesswork: graph A clearly has an average $>2$, whereas by computing the area of triangles you can find that the average of C and D are 2 and 4 respectively. To show that B has $>2$, just draw the triangle {(0,0),(6,0),(3,4)} : it is contained in the area of the curve and has area =2
    $endgroup$
    – user157321
    Jul 30 '14 at 12:58


















  • $begingroup$
    In general you would integrate the function (to find the area below the curve) and divide by the length of the interval ($b-a=6$ here) but I think what is expected here is just to use a bit of guesswork: graph A clearly has an average $>2$, whereas by computing the area of triangles you can find that the average of C and D are 2 and 4 respectively. To show that B has $>2$, just draw the triangle {(0,0),(6,0),(3,4)} : it is contained in the area of the curve and has area =2
    $endgroup$
    – user157321
    Jul 30 '14 at 12:58
















$begingroup$
In general you would integrate the function (to find the area below the curve) and divide by the length of the interval ($b-a=6$ here) but I think what is expected here is just to use a bit of guesswork: graph A clearly has an average $>2$, whereas by computing the area of triangles you can find that the average of C and D are 2 and 4 respectively. To show that B has $>2$, just draw the triangle {(0,0),(6,0),(3,4)} : it is contained in the area of the curve and has area =2
$endgroup$
– user157321
Jul 30 '14 at 12:58




$begingroup$
In general you would integrate the function (to find the area below the curve) and divide by the length of the interval ($b-a=6$ here) but I think what is expected here is just to use a bit of guesswork: graph A clearly has an average $>2$, whereas by computing the area of triangles you can find that the average of C and D are 2 and 4 respectively. To show that B has $>2$, just draw the triangle {(0,0),(6,0),(3,4)} : it is contained in the area of the curve and has area =2
$endgroup$
– user157321
Jul 30 '14 at 12:58










2 Answers
2






active

oldest

votes


















0












$begingroup$

Your equation for this question is:



$$frac{1}{6}*int_0^6 h(x) = 2$$



Therefore,



$$int_0^6 h(x) = 12$$



For answers $c$ and $d$ you can use the area of a triangle,



If you try answer choice $c$,



We get that:



$$A = frac{1}{2}*4.5*6 - frac{1}{2}*1.5*(-2) = 12$$



Therefore our answer is C.






share|cite|improve this answer









$endgroup$





















    0












    $begingroup$

    Graph A:
    The part for $xin[0,2)$ compensates with the part for $xin (2,4]$, giving an average of 2 over the interval $[0,4]$. But the part for $xin(4,6]$ is above the line $y=2$. So A is not good.



    GraphB:
    Define a new function $g$ whose graph is composed of one straight line between $(0,0)$ and $(3,4)$ and the other straight line between $(3,4)$ and $(6,0)$. Similarly as in case A, we can see average of the function $g$ is equal to 2. But the graph of $f$ is always above $g$. So B is not good.



    Similarly, we find average in graph C is 2 and average in Graph D is 4






    share|cite|improve this answer









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      2 Answers
      2






      active

      oldest

      votes








      2 Answers
      2






      active

      oldest

      votes









      active

      oldest

      votes






      active

      oldest

      votes









      0












      $begingroup$

      Your equation for this question is:



      $$frac{1}{6}*int_0^6 h(x) = 2$$



      Therefore,



      $$int_0^6 h(x) = 12$$



      For answers $c$ and $d$ you can use the area of a triangle,



      If you try answer choice $c$,



      We get that:



      $$A = frac{1}{2}*4.5*6 - frac{1}{2}*1.5*(-2) = 12$$



      Therefore our answer is C.






      share|cite|improve this answer









      $endgroup$


















        0












        $begingroup$

        Your equation for this question is:



        $$frac{1}{6}*int_0^6 h(x) = 2$$



        Therefore,



        $$int_0^6 h(x) = 12$$



        For answers $c$ and $d$ you can use the area of a triangle,



        If you try answer choice $c$,



        We get that:



        $$A = frac{1}{2}*4.5*6 - frac{1}{2}*1.5*(-2) = 12$$



        Therefore our answer is C.






        share|cite|improve this answer









        $endgroup$
















          0












          0








          0





          $begingroup$

          Your equation for this question is:



          $$frac{1}{6}*int_0^6 h(x) = 2$$



          Therefore,



          $$int_0^6 h(x) = 12$$



          For answers $c$ and $d$ you can use the area of a triangle,



          If you try answer choice $c$,



          We get that:



          $$A = frac{1}{2}*4.5*6 - frac{1}{2}*1.5*(-2) = 12$$



          Therefore our answer is C.






          share|cite|improve this answer









          $endgroup$



          Your equation for this question is:



          $$frac{1}{6}*int_0^6 h(x) = 2$$



          Therefore,



          $$int_0^6 h(x) = 12$$



          For answers $c$ and $d$ you can use the area of a triangle,



          If you try answer choice $c$,



          We get that:



          $$A = frac{1}{2}*4.5*6 - frac{1}{2}*1.5*(-2) = 12$$



          Therefore our answer is C.







          share|cite|improve this answer












          share|cite|improve this answer



          share|cite|improve this answer










          answered Jul 30 '14 at 12:55









          Varun IyerVarun Iyer

          5,317826




          5,317826























              0












              $begingroup$

              Graph A:
              The part for $xin[0,2)$ compensates with the part for $xin (2,4]$, giving an average of 2 over the interval $[0,4]$. But the part for $xin(4,6]$ is above the line $y=2$. So A is not good.



              GraphB:
              Define a new function $g$ whose graph is composed of one straight line between $(0,0)$ and $(3,4)$ and the other straight line between $(3,4)$ and $(6,0)$. Similarly as in case A, we can see average of the function $g$ is equal to 2. But the graph of $f$ is always above $g$. So B is not good.



              Similarly, we find average in graph C is 2 and average in Graph D is 4






              share|cite|improve this answer









              $endgroup$


















                0












                $begingroup$

                Graph A:
                The part for $xin[0,2)$ compensates with the part for $xin (2,4]$, giving an average of 2 over the interval $[0,4]$. But the part for $xin(4,6]$ is above the line $y=2$. So A is not good.



                GraphB:
                Define a new function $g$ whose graph is composed of one straight line between $(0,0)$ and $(3,4)$ and the other straight line between $(3,4)$ and $(6,0)$. Similarly as in case A, we can see average of the function $g$ is equal to 2. But the graph of $f$ is always above $g$. So B is not good.



                Similarly, we find average in graph C is 2 and average in Graph D is 4






                share|cite|improve this answer









                $endgroup$
















                  0












                  0








                  0





                  $begingroup$

                  Graph A:
                  The part for $xin[0,2)$ compensates with the part for $xin (2,4]$, giving an average of 2 over the interval $[0,4]$. But the part for $xin(4,6]$ is above the line $y=2$. So A is not good.



                  GraphB:
                  Define a new function $g$ whose graph is composed of one straight line between $(0,0)$ and $(3,4)$ and the other straight line between $(3,4)$ and $(6,0)$. Similarly as in case A, we can see average of the function $g$ is equal to 2. But the graph of $f$ is always above $g$. So B is not good.



                  Similarly, we find average in graph C is 2 and average in Graph D is 4






                  share|cite|improve this answer









                  $endgroup$



                  Graph A:
                  The part for $xin[0,2)$ compensates with the part for $xin (2,4]$, giving an average of 2 over the interval $[0,4]$. But the part for $xin(4,6]$ is above the line $y=2$. So A is not good.



                  GraphB:
                  Define a new function $g$ whose graph is composed of one straight line between $(0,0)$ and $(3,4)$ and the other straight line between $(3,4)$ and $(6,0)$. Similarly as in case A, we can see average of the function $g$ is equal to 2. But the graph of $f$ is always above $g$. So B is not good.



                  Similarly, we find average in graph C is 2 and average in Graph D is 4







                  share|cite|improve this answer












                  share|cite|improve this answer



                  share|cite|improve this answer










                  answered Jul 30 '14 at 13:01









                  Petite EtincellePetite Etincelle

                  12.4k12148




                  12.4k12148






























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