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Math Help - Functions help

  1. #1
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    Functions help

    Hey guys. I'm about to start grade 11 and I've always had a lot of trouble with high school math. I looked back at my summer school stuff (I started gr11 math early) and I'm puzzled by this question: Complete the following table then sketch the graph for the equation x = y squared. The y "elements" or Range as I'm taught to call it now are as follows: -3, -2 , -2 ,0, 1 ,2, 3.

    The question I'm stuck on is this: Is x=y squared a function or a relation?

    Ps- Would describing the graph i made help in any way?

    Thanks in advance!
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  2. #2
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    You need a definition of a function. Do your materials provide such a definition?

    Most clearly, if 2 y-values lead to the same x-value, you've a relation and not a function. In this case:

    y = 1 ==> (1^2) = 1
    y = -1 ==> ((-1)^2) = 1

    What does that say about function or relation?
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  3. #3
    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by Obama View Post
    Hey guys. I'm about to start grade 11 and I've always had a lot of trouble with high school math. I looked back at my summer school stuff (I started gr11 math early) and I'm puzzled by this question: Complete the following table then sketch the graph for the equation x = y squared. The y "elements" or Range as I'm taught to call it now are as follows: -3, -2 , -2 ,0, 1 ,2, 3.

    The question I'm stuck on is this: Is x=y squared a function or a relation?

    Ps- Would describing the graph i made help in any way?

    Thanks in advance!
    Make a table of values and plot them on a pair of axis. put the y-elements in one column and calculate the respective x-elements (by following the formula).

    example.

    x = y^2

    \Rightarrow when y = -3:

    x = (-3)^2 = 9

    so: x = 9, y = -3 is the first row of the table


    when you calculate the x-values for all the y-values, then just plot the points on the axis (do you know how to do that?)

    Hint: For the second part. A function is a special type of relation. A function is a relation in which each element in the domain maps to one and ONLY one element in the range, that is, each output has a unique input


    EDIT: You're too fast for me, TKHunny
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  4. #4
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    I understand now, about 80% now lol. Thanks for your explanations and your time.
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  5. #5
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    It's probably important to point out that relations are okay. You may hear the functions are good and relations are bad. Forget it. They are just definitions. Learn them, learn the difference, and learn to use both.
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