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Student Support Forum: 'Evaluating a minimum and plotting solution' topicStudent Support Forum > General > "Evaluating a minimum and plotting solution"

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Phil Lederer
03/24/08 3:41pm

I am trying to do something basic--but I cannot figure it out


I have some function in two variables

f[x_,y_]= some arbitrary polynomial

Now I want to minimize the function with respect to y over some
compact interval with fixed x

NMinimize[{f[x,y],y≥5,y≤9},y]

I want to plot the y's versus the x's.

I have tried many things like defining

s[x_]=Part[NMinimize[{f[x,y],y≥5,y≤9},y],2]

Plot[s[x],{x,-14, 46}]

or variations

Plot[tt/.s[x],{x,-14, 46}].

Many error messages or nothing at all results.........

I am sure this is easy, and someone can suggest how to do this.

However, one more thing would be greatly helpful (give a man a decent
and readable Mathematica manual and he can feed himself...)

I am baffled by what Mathematica wants when it comes to using a single
part of a list and changing it to a scalar. Suppose as above q is a
vector with a rule assigning a value to some variable x that is x-
some number, and this assignment is in the third position of the list

What is going on with q/.d[[3]] for example: Is q now a scalar? If
not why not?

Thanks for you help,

Phil Lederer


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Subject (listing for 'Evaluating a minimum and plotting solution')
Author Date Posted
Evaluating a minimum and plotting solution Phil Lederer 03/24/08 3:41pm
Re: Evaluating a minimum and plotting solution yehuda ben-s... 03/28/08 12:54pm
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