A function take an input and produce a unique output.
[tex]y=2^x[/tex]
y is the output
x is the input
[tex]\begin{gathered} x=1y=2^x=2^1\text{ = 2} \\ x=2y=2^{2\text{ = 4}} \\ x=3y=2^3\text{ = 8} \\ x=4y=2^4\text{ = 16} \\ x=5y=x^5\text{ = 32} \end{gathered}[/tex]
