In the basics, it is just a set of Relations.
A relation is just a paring of x and y
x is called the domain.
y is called the range.
So a function is where: only one member of the domain corresponds with only one member of the range.
Test for a function: vertical line test
yes --> vertical line only hits once
not --> vertical line hits more than once
Notation
f(x)-->"f of x"
The symbol can now take the place of "y"
For example y=3x-7 ----> f(x)=3x-7
Evaluating functions
The function is f(x)=2x+3
what ever number you place in the f of x's x will replace every where you see x though out the whole equation.
Ex.
f(x)=3x-2
f(2)=3(2)-2
f(2)=6-2
f(2)=4
R;T---> T+2
R;(2)--->1(2)+2
R;(2)--->2+2
R;(2)--->4
f(x)=3x-2 G(x)=4x-3
G(f(x))
f(x)=3x-2
f(2)=3(2)-2
f(2)=6-2
f(2)=4
G(f(4))=4x-3
G(f(4))=4(4x-3)-3
G(f(4))=8x-15