The concept of function is input and output which also well known as X and Y. When you input a number into an equation,it produces an output (Y).Does it sound a little bit complicated? Then let's see an example about it!
We have an equation Y=X+1.We just learned that X is the input,so we can easily change it to any number we want to be the input. If X=1,then the equation becomes Y=1+1,therefore,y=2.We then know that when X=1,Y=2.We can use the same way to find the other outputs!
Now we have a table of values which helps us to evaluate and graph the function(Sometime it is not necessary)
So far so good?Then let's learn some rules about the world of functions.
We always use f(x)= to represent a function. For example,f(x)=x+1.
It's really easy isnt it?Then let's learn some more exciting stuff.
We know that X is the input,Y is the output. In order to make the function more visual and direct ,we can turn it into a graph.
This is a graph