Final answer:
The given functions can be checked for permutation by examining whether each element in the domain has a unique image in the codomain.
Step-by-step explanation:
The given functions can be checked for permutation by examining whether each element in the domain has a unique image in the codomain.
- The function f1(x) = x + 1 is a permutation of R because for every real number x, there exists a unique result of x + 1 in the codomain.
- The function f2(x) = x^2 is not a permutation of R because it fails the horizontal line test. For example, both -2 and 2 map to the same value, 4, in the codomain.
- The function f3(x) = -x is a permutation of R because for every real number x, there exists a unique result of -x in the codomain.