Mark the correct alternative in each of the following:
Let f be an injective map with domain {x, y, z} and range {1, 2, 3} such that exactly one of the following statements is correct and the remaining are false.
f(x) = 1, f(y) ≠ 1, f(z) ≠ 2.
The value of f–1(1) is
Given that f is an injective map with domain {x, y, z} and range {1, 2, 3}.
Case-1
Let us assume that f(x) =1 is true and f(y) ≠ 1, f(z) ≠ 2 is false.
Then f(x) = 1, f(y) = 1 and f(z) = 2.
This violates the injectivity of f because it is one-one.
Case-2
Let us assume that f(y) ≠1 is true and f(x)= 1, f(z) ≠ 2 is false.
Then f(x) ≠ 1, f(y) ≠ 1 and f(z) = 2.
This means there is no pre image of 1 which contradicts the fact that the range of f is {1, 2, 3}.
Case-3
Let us assume that f(z) ≠2 is true and f(x)= 1, f(y) ≠ 1 is false.
Then f(z) ≠ 2, f(y) = 1 and f(x) ≠1.
⇒ f–1(1) = y