# Inflection Points

• Nov 15th 2009, 04:33 PM
rawkstar
Inflection Points
I am given a graph of a derivative to some function. (i don't know the equation of the function or the derivative). I need to list the x coordinates of the inflection points of the graph. what would these be and how can i spot them from the derivative graph?
• Nov 15th 2009, 04:37 PM
skeeter
Quote:

Originally Posted by rawkstar
I am given a graph of a derivative to some function. (i don't know the equation of the function or the derivative). I need to list the x coordinates of the inflection points of the graph. what would these be and how can i spot them from the derivative graph?

points on the graph where the slope of f' changes sign.
• Nov 15th 2009, 04:39 PM
rawkstar
so where the derivative graph is crosses the x axis?
also on mine, there is a part where the graph is negative touches the x axis and then continues to be negative again. would that be an inflection point?
• Nov 15th 2009, 04:41 PM
skeeter
Quote:

Originally Posted by rawkstar
so where the derivative graph is crosses the x axis? no

also on mine, there is a part where the graph is negative touches the x axis and then continues to be negative again. would that be an inflection point?

did you read and understand what I said previously?
• Nov 15th 2009, 04:44 PM
rawkstar
okay im rethinking it now.
so there is a part of the graph that is linear changing from positive to negative. at the end of this line the derivative graph turns into an upside down u parabola which stays under the x axis.
from what i thnk you're saying, the inflection point would be the end of the line where it turns into a parabola. is this right?
• Nov 15th 2009, 04:49 PM
skeeter
Quote:

Originally Posted by rawkstar
okay im rethinking it now.
so there is a part of the graph that is linear changing from positive to negative. at the end of this line the derivative graph turns into an upside down u parabola which stays under the x axis.
from what i thnk you're saying, the inflection point would be the end of the line where it turns into a parabola. is this right?

only if the slope of the graph changes sign there.