Determine if the function f:R→R defined by f(x) = (X^2+1)/(X^2+2) is a bijection.Explain
问题描述：
Determine if the function f:R→R defined by f(x) = (X^2+1)/(X^2+2) is a bijection.Explain
答
不是。 因为 f(-x)=f(x).
答
f is not bijiection
proof:
we can find tow members of R ,1 and -1 such that
f(-1)=f(1) = 2/3
so f is not into.
because bijection must be both into and onto.
therefore f is not bijection.