(용어) "root" or "zero"

어떤 함수의 zero 라는 건 함수값이 0 이 되는 그 함수 정의역 위의 점을 말한다. 처음 이 용어 볼 때 해석하느라 혼란스러웠음.. 

Root (mathematics)

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This article is about the zeros of a function, which should not be confused with the value at zero. You may also want information on the Nth roots of numbers instead.

In mathematics, a root (or a zero) of a complex-valued function ƒ is a member x of the domain of ƒ such that ƒ(x) vanishes at x, that is,

in other words, a "root" of a function f is a value for x that produces a result of zero ("0"). For example, consider the function f defined by the following formula:

This function has a root at 3 because f(3) = 3² − 6(3) + 9 = 0.

If the function is mapping from real numbers to real numbers, its zeros are the points where its graph meets the x-axis. The x-value of such a point is called x-intercept. Therefore in this situation a root can be called an x-intercept.

The word root can also refer to the nth root of a number, a, as in . The square root of a number, a, is .

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