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anonymous

  • one year ago

Write the summation to estimate the area under the curve y = 2x2 + 1 from x = 0 to x = 4 using 4 rectangles and left endpoints.

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  1. anonymous
    • one year ago
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    https://gyazo.com/10fefff1c824a71908fefa15fce74b76 It's A, right? Just making sure I got the right answer, haven't don math in quite some time.

  2. anonymous
    • one year ago
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    @dinamix

  3. dinamix
    • one year ago
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    yup its great mate @Ephemera

  4. anonymous
    • one year ago
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    I got it wrong :(

  5. zzr0ck3r
    • one year ago
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    @dinamix this is once again why just giving answers can be bad, you don't know the answer is wrong that you gave...

  6. zzr0ck3r
    • one year ago
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    @Ephemera would you like to learn how to do this?

  7. dinamix
    • one year ago
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    lol @zzr0ck3r he tell me do that

  8. anonymous
    • one year ago
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    Of course @zzr0ck3r

  9. zzr0ck3r
    • one year ago
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    remember we don't start at the beginning of the interval, which here you chose 0. If we put it into 4 parts, from 0 to 4, we would use the interval [0,1], [1,2], [2,3], and [3,4]. When we take the width of the first interval, we have 1, so we start at 1 not 0. So what is the right answer?

  10. anonymous
    • one year ago
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    It would be D, right?

  11. zzr0ck3r
    • one year ago
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    correct

  12. zzr0ck3r
    • one year ago
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    remember last time, \(x_1=4.5\) not \(4\) even though we were on the interval \([4,6]\).

  13. dinamix
    • one year ago
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    \[\sum_{i=1}^{4}(2i^2+1) = 3+9+19+33\] @Ephemera i think should be like that

  14. anonymous
    • one year ago
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    So if it was for example 3 to 5, I'd divide it into 3,3.5,4,4.5?

  15. zzr0ck3r
    • one year ago
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    once again, @dinamix just giving the answer would not help really, with logic and reasoning you can lead them to the correct answer.

  16. zzr0ck3r
    • one year ago
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    @Ephemera yes, if they said 4 intervals

  17. zzr0ck3r
    • one year ago
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    well no, it would be 3.5, 4, 4.5, 5

  18. zzr0ck3r
    • one year ago
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    this is assuming they want right triangles, which is pretty normal

  19. zzr0ck3r
    • one year ago
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    but the intervals would be [3,3.5], [3.5,4], [4,4.5], [4.5, 5]

  20. anonymous
    • one year ago
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    Ok, think I got it I reset my exam because I got a low grade on the last....can you check over my work @zzr0ck3r?

  21. dinamix
    • one year ago
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    @zzr0ck3r wow u are good teacher i like u ;)

  22. zzr0ck3r
    • one year ago
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    Just post questions as you have them, I am not sure how ethical that is...

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