f(1) = 3 and f(2) = 5.
Find the co-domain of this function.
According to the definition in Hung Fung Pure Maths textbook, the answer should be {3, 5}.
However, my textbook says that the answer is {3, 4, 5}.
I wonder if my textbook is wrong?!
{3, 4, 5} should be the range, not the co-domain.
Anyone here can explain which is right? Thanks.
更新1:
To myisland8132: Hung Fung (Calculus I) p.5: Let f: A -> B Then f[A]: {y: y = f(x) for some x in A} is the codomain of f and f[A] is a subset of B. So, Hung Fung is wrong?
