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Estimating area under the graph

  • Thread starter hahaha158
  • Start date
  • #1
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Homework Statement



Estimate the area under the graph of f(x)=3+x^2 from x=−1 to x=2 using six approximating rectangles and right endpoints.






The Attempt at a Solution



I've tried this multiple times but can't seem to get it, can someone tell me if i am on the right track?

i have

summation [3/6(3+(-1+i/6)^2)]

where i starts at -1 and increases by .5 passing through (-1,-0.5,0,0.5,1,1.5)

(I'm not sure about how the i increases)

Can anyone tell me what i am doing wrong?
 

Answers and Replies

  • #2
SteamKing
Staff Emeritus
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Start with a picture of the problem.

Show the widths and heights of your 6 rectangles.
 
  • #3
HallsofIvy
Science Advisor
Homework Helper
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Homework Statement



Estimate the area under the graph of f(x)=3+x^2 from x=−1 to x=2 using six approximating rectangles and right endpoints.






The Attempt at a Solution



I've tried this multiple times but can't seem to get it, can someone tell me if i am on the right track?

i have

summation [3/6(3+(-1+i/6)^2)]

where i starts at -1 and increases by .5 passing through (-1,-0.5,0,0.5,1,1.5)
This is an error. Because you are using right endpoints, the heights of the rectangles are determined at -0.5, 0, 0.5, 1, 1.5, and 2.

(I'm not sure about how the i increases)

Can anyone tell me what i am doing wrong?
I would second SteamKing's suggestion that you actually draw the rectangles. You seem to be trying to apply a formula without understanding it.
 

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