# how to find stationary point of a multivariable function [closed]

I am quite new, how can I find minumum, maximum or saddle point the following multivariable function by using mathematica $f(x,y)= 2x^3 +6xy^2 −3y^3 −150x$

## closed as off-topic by Michael E2, MarcoB, yohbs, m_goldberg, zhkMar 22 '17 at 3:20

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• "This question arises due to a simple mistake such as a trivial syntax error, incorrect capitalization, spelling mistake, or other typographical error and is unlikely to help any future visitors, or else it is easily found in the documentation." – Michael E2, MarcoB, yohbs, m_goldberg, zhk
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• Isn't you $x$ derivative always positive? so no min/max/saddle? – BlacKow Mar 21 '17 at 22:12
• Thank you for your interest. I updated the question. – HD239 Mar 21 '17 at 22:22
• Saddle Points and Inflection Points: Wolfram Demonstrations Project; and using Minimize and Maximize shows that your exemplary function does not have a min/max. – corey979 Mar 21 '17 at 22:34
• Is it Mathematica software question or general math question? – BlacKow Mar 21 '17 at 22:44
• See the "Applications" section of the docs for Grad. – Michael E2 Mar 21 '17 at 22:48