[求助]GWD-21-3

菲菲

Q3:

If f is the function defined by f(x) = 2x for x ≥ 0 and f(x) = x² for x < 0, what is the value of f(c) ?

(1)  /c/  = 2

(2)     c < 0

                  

Ans is A, but I think there are 2 values, so it cannot be determined.

Can anyone explain?

thinkers

c = -2 => f(c) = (-2)^2 = 4

c = 2 => f(c) = 2*2 = 4

x has 2 values but f(c) only has 1 value.

A