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Thread: Problem with imaginary numbers

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  1. #12
    Fanatic Member bugzpodder's Avatar
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    sqrt(x) is equilvalent x^(1/2) -- they are interchangable.
    x^(1/2), exactly like sqrt(x) and every other function, gives only one answer. the definition of a function is to only have one answer. there is no such thing as one-to-many functions. for every x, you are going to get precisely one value for f(x). therefore restrictions for the domain values are often understood.

    such as f(x)=sqrt(x). it is understood that x>=0.

    an example of one-to-many "equation" (I can't think of a more proper term) would be like for example x^2+y^2=1
    if you throw in any x, (restrictions here would be abs(x)<=1), you'll get two values for y (except when x=1), one positive, one negative. you can see by drawing a vertical line with the absolute value of x coordinate less than to 1, it'll intersect at two distinct points, thus the two y-values.

    something similar to what you may have actually being talking about would be x^2, as take a look at this example:

    x^2=9
    abs(x)=sqrt(9)
    abs(x)=3
    x=3,-3

    the *better* way to do the example is to do the difference of squares
    x^2=9
    x^2-9=0
    (x-3)(x+3)=0
    x=3,-3
    Last edited by bugzpodder; Jul 29th, 2002 at 07:52 PM.

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