Question

f:N-->N f(×)=x-(-1)^x then f is

One one

Onto

Many one

Into

Answer 1

For every odd value of x, we have f(x)=x-(-1))=x+1
For every even value of x, we have f(x)=x-(1)=x-1

We observe that for x=1, f(x) is 2
For x=2, f(x)=1
For x=3, f(x)=4
For x=4, f(x)=3
For each value of x, we get different values of f(x)
Hence the function is one-one (Answer)