Inequalities

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  1. Kravez's Avatar
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    • Posts: 382
    Inequalities
    When you plot this inequality onto a graph:  y > 4x

    Shouldn't it be for every 1 across you go 4 up?

    How come on here http://www.sci2.co.uk/fmaths/D1/D1%2...20Jan%20MS.pdf

    Question 7 a) they plotted y = 4x differently?
    Last edited by Kravez; 17-05-2012 at 16:35.
  2. Implication's Avatar
    • Benevolent Member
    • Posts: 890
    Re: Inequalities
    They didn't It looks fine to me. At x=10, y=40; at x=20, y=80 etc. etc. What do you think is wrong with it?
  3. Kravez's Avatar
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    Re: Inequalities
    (Original post by Implication)
    They didn't It looks fine to me. At x=10, y=40; at x=20, y=80 etc. etc. What do you think is wrong with it?
    Look closely at (0,0). For every 1 across they are going 2 up.
  4. Pride's Avatar
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    • Location: London
    Re: Inequalities
    (Original post by Kravez)
    Look closely at (0,0). For every 1 across they are going 2 up.
    every 40 up, 10 across.
    therefore it must be right.
  5. bananarama2's Avatar
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    Re: Inequalities
    (Original post by Kravez)
    Look closely at (0,0). For every 1 across they are going 2 up.
    Look at the scale.
  6. Implication's Avatar
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    • Posts: 890
    Re: Inequalities
    (Original post by Kravez)
    Look closely at (0,0). For every 1 across they are going 2 up.
    The axes aren't scaled equally. Look again: one square on the x-axis is 1; 1 square on the y-axis is 2. Thus, going 1 SQUARE across for every 2 SQUARES up is the same as going 1 unit across for every 4 units up.
  7. Kravez's Avatar
    • Banned
    • Posts: 382
    Re: Inequalities
    (Original post by Implication)
    They didn't It looks fine to me. At x=10, y=40; at x=20, y=80 etc. etc. What do you think is wrong with it?

    (Original post by Kravez)
    Look closely at (0,0). For every 1 across they are going 2 up.

    (Original post by Pride)
    every 40 up, 10 across.
    therefore it must be right.

    (Original post by wcp100)
    Look at the scale.

    (Original post by Implication)
    The axes aren't scaled equally. Look again: one square on the x-axis is 1; 1 square on the y-axis is 2. Thus, going 1 SQUARE across for every 2 SQUARES up is the same as going 1 unit across for every 4 units up.
    My mistake,

    Thanks.
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