Evaluating and Graphing Piecewise Functions

Evaluating: With the evaluating portion, you have the function (EX.1), you would then be given a set of "X" values to use for the function. The object is to look at the function and decide which value goes into which of the 2 equations. Its like matching, but with math afterwards.

EX.1: f(x) = {X+2, if X<2

{2X+1, if X>2

A) X=0; for this value, since 0<2, you would use the top equation and solve as normal.

B) X=2; for this value, since 2<2 and 2>2 and both

False, this value is impossible to use in the function.

C) X=4; Since 4>2, you would use the bottom equation

And solve as normal.

Once you have the values with the right equation,

You just plug the "X" value in place of "X".

*for the "you try it", use the function below:

F(x)= {X-3, if X>4

{3X+5, if X<3

EXAMPLES	YOU TRY IT*
A) X=0; f(x) = X+2 f(0) = 0+2 = 2	A) X=0
B) Not possible	B) X=7
C) X=4; f(x) = 2X +1 f(4) = 2(4) +1 = 9	C) X=2

Graphing: Now, no math is involved, but graphing these is a little tricky. Although you are just graphing lines, you don't graph the whole line so you have to know where to start.

First, look at the function as two separate equations and this will be a lot easier. Graph the line as normal, but for the part where it says: "if X<#" start the line where the # is on the graph. (EX.2)

EX.2: f(x) = {X+2, if X>1

{2X +1, if X<0