Question

which of the following is a function from { 1,2,3,4,5} to {1,2,3,4,5} that is one-to-one and onto?
a){(1,2) (2,3) (3,4) (4,5) (5,5)}
b) {(1,5) (2,4) (3,3,) (4,2) (5,1)}
c){(1,3) (2,3) (3,3) (4,3) (5,3)}

Answer 1

the one where the first and second numbers do not repeat

Answer 2

in a) the 5 repeats, so not that one

Answer 3

looks like b)

Answer 4

thank you :)
there is no way I can show work right?

Answer 5

no you just have to look

Answer 6

one to one means
\[f(a)=f(b)\iff a=b\] but there is nothing to compute here, you just have to check

Answer 7

alright, thanks.