# What is a zero of a function?

##### 1 Answer
Jan 27, 2015

A zero of a function is an interception between the function itself and the X-axis.
The possibilities are:

• no zero (e.g. $y = {x}^{2} + 1$) graph{x^2 +1 [-10, 10, -5, 5]}
• one zero (e.g. $y = x$) graph{x [-10, 10, -5, 5]}
• two or more zeros (e.g. $y = {x}^{2} - 1$) graph{x^2-1 [-10, 10, -5, 5]}
• infinite zeros (e.g. $y = \sin x$) graph{sinx [-10, 10, -5, 5]}

To find the eventual zeros of a function it is necessary to solve the equation system between the equation of the function and the equation of the X-axis ($y = 0$).