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what is the critical points in this equation F(x) = x^3-3x^2+3x+1?

 Nov 21, 2016
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what is the critical points in this equation F(x) = x^3-3x^2+3x+1?

 

Mr Google tells me that critical point is what Americans call stationary points.

 

Ok well that is when the first derivative =0

 

F(x) = x^3-3x^2+3x+1

 

F'(x) = 3x^2-6x+3

3x^2-6x+3=0

x^2-2x+1=0

(x-1)^2=0

x=1   

F(1) = 1-3+3+1=2

so the only critical point is (1,2)

 

F''(x) = 6x-6

F''(1) = 6-6=0 Mmm

 

As x tends to 1 from above, f"(x)>0    concave up

As x tends to 1 from below, f"(x)<0    concave down

 

So at (1,2) there is a horizontal point of inflection.

 

 Nov 21, 2016

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