Signum Function

f: R → R

This is known as signum function.

Let us check value of f(x) for different values of x

For x = –1

x < 0

So, f(x) = –1

For x = –2

x < 0

So, f(x) = –1

For x = 1

x > 0

So, f(x) = 1

For x = 2

x > 0

So, f(x) = 1

For x = 0

x = 0

So, f(x) = 0

Now,

Plotting graph

Here,

Domain = All values of x = R

Range = All values of y

Since y will have value 0, 1 or –1

Range = {0, 1, –1}