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#### confusedatmath

##### New member

- Jan 2, 2014

- 14

Let me clarify what I understand (feel free to correct me).

If we derive an equation and let it = 0, the value of x is some kind of turning point.

To find out what kind, we derive again, and sub that value of x , and look for the following.

if x > 0 it is a local min

if x < 0 is it a local max

if x = 0 it is an inflection point.

example.

y= (x-1)^3 + 1

is this a local max/min/inflection point at (1,1)

so

derive 1st time = 3(x-1)^2 = 3x^2 -6x +3

we let it equal 0 so

0 = 3x^2 -6x +3

x =1

then we derive again to know what kind of turning point.

derive 2nd time = 6x -6

sub x=1

6(1)-6 = 0

therefore it is an inflection point??

is this right... hmmmm