Okay, I have made up this rule. I would love to call it mine, but I am sure some one is bound to have invented it by now...(adsbygoogle = window.adsbygoogle || []).push({});

f(x)

find a such that f '(a)=0

now find the first nth derivative such that f^n(a) !=0

Usually n=2.

1. If n E odd - Inflexion, If n E even, keep going...

2. If f^n(a)>0 - Minima, If f^n(a)<0 - Maxima.

Well that is the jist of it...

Is it valid?

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# 2nd Derivative Test conquered?

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