# Homework Help: Help Graphing Piece Wise Function Please

1. Jul 27, 2010

### GreenPrint

1. The problem statement, all variables and given/known data

Having some trouble graphing this

y = 3 - x for x less then or equal to 1
y = 2x for x greater than one

how do I indicate that for the first part (1, 2) there would be a closed point at that cordinate but for the second part an open point at those same exact cordinates how do I indicate this on my graph?

2. Relevant equations

3. The attempt at a solution

2. Jul 27, 2010

### hgfalling

Well, your function seems to be continuous, so there is no "open circle" for the second part of the function. If, say, y=3x for x > 1, then you would draw an open circle at (1,3) and a closed one at (1,2). But here, you just draw the two lines connected at (1,2).

3. Jul 27, 2010

### praharmitra

you do not indicate that. You are plotting the entire function, not its individual pieces. And (1,2) is a closed point for the function.

4. Jul 27, 2010

### hgfalling

Let me clarify. When graphing a function that is piecewise continuous but discontinuous at a point, you indicate the function value at the discontinuity with a closed circle on the piece that contains the function value, and an open point on the piece that does not. When graphing the function here, the function is everywhere continuous, and so it is not necessary to explicitly denote the function value at the point where the function is piecewise defined differently with any kind of special circle. You can just draw the two lines connected.