• somegeek
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    10 months ago

    I’m not a math guru but there are only 4 shapes in this and there are 5 functions? You can describe a circle with a single function. Someone explain?

    • Chrobin@discuss.tchncs.de
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      10 months ago

      Well, you can describe a circle with a single function if you look at a function R -> R^2. But a circle can’t be the graph of a single function.

    • akari@lemmy.blahaj.zone
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      10 months ago

      f and g form the top an bottom of the circle. note that they only differ by a single sign

      you need two of them because a circle can’t be expressed by a single function of x as it needs to map every x value to 0 to 2 y values

    • Alien Nathan Edward@lemm.ee
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      10 months ago

      A graph is just a series of correlated points, a formula to tell you that when x is set to a certain value y has a different value. It follows then that no single function can define a circle because for every given value of x there would have to be two potential values of y.