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anonymous

  • one year ago

HELP!! Does this make any sense?! http://mhf4u1.pbworks.com/w/page/26838563/Application%20Problem

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  1. anonymous
    • one year ago
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    THIS part!!

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  2. anonymous
    • one year ago
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    i dont understand how they got that :(

  3. Loser66
    • one year ago
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    What don't you get?

  4. anonymous
    • one year ago
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    how did they get b/w 9-13 necklaces ??

  5. Loser66
    • one year ago
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    the intersections between the graphs|dw:1436711669825:dw|

  6. anonymous
    • one year ago
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    no but i graphed it and the points were 3 and 19

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  7. Loser66
    • one year ago
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    |dw:1436711704284:dw|

  8. anonymous
    • one year ago
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    yes

  9. Loser66
    • one year ago
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    and between 9 and 13, parabola is higher than the line right?

  10. Loser66
    • one year ago
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    that is the revenue > the cost, right?

  11. Loser66
    • one year ago
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    @freckles please help me to finish the explanation. I have to go now.

  12. anonymous
    • one year ago
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    isnt the parabola higher at 3-19?!

  13. anonymous
    • one year ago
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    PL HELP!!!

  14. anonymous
    • one year ago
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    @misssunshinexxoxo

  15. misssunshinexxoxo
    • one year ago
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    @jim_thompson5910

  16. anonymous
    • one year ago
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    i think it should be "steph should make 3-19 necklaces each week"

  17. anonymous
    • one year ago
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    maybe the website is wrong?!??! because it doesnt make sense to me otherwise :(

  18. freckles
    • one year ago
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    \[25n-n^2>55+3.5n \\ 0>n^2+3.5n-25n+55 \\ n^2-21.5n+55<0 \\ 10n^2-215n+550<0 \\ 2n^2-43n+110<0 \\ \text{ this does give } n \in (3,19)\]

  19. freckles
    • one year ago
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    oops \[n \in [3,19]\]

  20. freckles
    • one year ago
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    wanted to but brackets there to show to include the endpoints

  21. freckles
    • one year ago
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    since actually you have the lower endpoint is approximately n=2.97 and the upper endpoint is 18.53 so you could actually say the answer is [3,19) didn't include the 19 because 18.53 is less than 19 but definitely include the 3 since 3 is more than 2.97

  22. freckles
    • one year ago
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    it looks like there was some dyslexia happening there on the website though :p

  23. anonymous
    • one year ago
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    omg so i was right?! its b/w 3-19 ?

  24. anonymous
    • one year ago
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    not 13-9?

  25. freckles
    • one year ago
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    yep the weird thing is they even put the right answer after they said the wrong answer

  26. anonymous
    • one year ago
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    yeah thats what got me confused

  27. anonymous
    • one year ago
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    thanks a ton though!! :)

  28. freckles
    • one year ago
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    np

  29. anonymous
    • one year ago
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    @freckles FRECKLES!!! How did you get

  30. anonymous
    • one year ago
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    n∈[3,19]

  31. anonymous
    • one year ago
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    ??

  32. freckles
    • one year ago
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    well actually n in [3,19) since 19 is a little greater than the actual left endpoint

  33. anonymous
    • one year ago
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    where did you get the points 3,19? from the graph? or did you get that from the 25n-n^2>55+3.5n??

  34. freckles
    • one year ago
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    \[2n^2-43n+110<0 \\ 2n^2-43n<-110 \\ n^2-\frac{43}{2}n<-55 \\ n^2-\frac{43}{2}n+(\frac{43}{2} \frac{1}{2})^2<-55+(\frac{43}{2} \frac{1}{2})^2 \\ (n-\frac{43}{4})^2<-55+\frac{43^2}{4^2} \\ (n-\frac{43}{4})^2<\frac{-55(16)+43^2}{16} \\ (n-\frac{43}{4})^2<\frac{969}{16} \\ \sqrt{ (n-\frac{43}{4})^2}< \sqrt{\frac{969}{16}} \\ |n-\frac{43}{4}|<\frac{ \sqrt{969}}{4} \\ - \frac{\sqrt{969}}{4}<n-\frac{43}{4}< \frac{\sqrt{969}}{4} \\ \frac{43}{4}-\frac{\sqrt{969}}{4}<n<\frac{\sqrt{969}}{4}+\frac{43}{4} \]

  35. freckles
    • one year ago
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    I solve the quadratic inequality I had above

  36. anonymous
    • one year ago
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    so how'd you get 3 and 19 from all that?!

  37. freckles
    • one year ago
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    calculator to approximate both the 43/4-sqrt(969)/4 and 43/4+sqrt(969)/4

  38. anonymous
    • one year ago
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    sorry im being so difficult, i just really dont understand :(

  39. freckles
    • one year ago
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    \[\frac{\sqrt{969}}{4}+\frac{43}{4} \approx 18.5322 \\ \frac{43}{4}-\frac{\sqrt{969}}{4} \approx 2.96781\]

  40. anonymous
    • one year ago
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    ohhhhhhh alright

  41. anonymous
    • one year ago
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    thank you soo so so much omg

  42. freckles
    • one year ago
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    \[2.96781<n<18.5322 \] n can be a whole number only 3 is in that interval but 19 isn't so you can say the inequality is: \[3 \le n <19\]

  43. freckles
    • one year ago
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    or an interval notation [3,19)

  44. freckles
    • one year ago
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    in roster notation {3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18}

  45. freckles
    • one year ago
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    by the way when we say n in [3,19) we should also include where n is a whole number (or you can say integer or whatever )

  46. freckles
    • one year ago
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    lol just trying to be really proper with all the math terminology :p

  47. anonymous
    • one year ago
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    so is it 3

  48. anonymous
    • one year ago
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    ** \[3\le n \le 19\]

  49. freckles
    • one year ago
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    well I put \[3 \le n < 19\] since 19 isn't actually included

  50. freckles
    • one year ago
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    where n is integer of course

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