Finding the x that makes y minimum in MATLAB.

[btbam91]

Hello.

As stated in the title, I have a function y that is in terms of x. How do I go about determing the 'x' that makes 'y' a minimum?

Thanks!

 

[jhae2.718]

Think calculus: how can you find a minimum of a function? Then, it's just a matter of telling MATLAB to do this.

 

[btbam91]

Duhhh, I guess I was just being lazy and expecting a MATLAB function to handle it for me.

Thanks!

 

[manyoolo]

Hi
Is there anyone help me with Matlab
I have got different data series of x and y, and want to plot them in a single xy plot using a single written program, can you advice?
Emmanuel

 

[jhae2.718]

@btbam91:
If you have data in vector form, you can use diff() or polyder(). You might actually be able to do:

[yMin I] = min(y)
% corresponding x is:
x(I)

Symbolically, you can use diff() and then solve().

@manyoolo:
"hold on" will allow multiple data to be plotted on the same plot.

 

[Chrisas]

Hi
Is there anyone help me with Matlab
I have got different data series of x and y, and want to plot them in a single xy plot using a single written program, can you advice?
Emmanuel

This:
plot(x1,y1,x2,y2,x3,y3);

or if all x and y's are same length:
plot( [ x1 x2 x3 ], [ y1 y2 y3]);

or as already mentioned:
plot(x1, y1);
hold on;
plot(x2, y2);
plot(x3, y3);
hold off;

 

[manyoolo]

@btbam91:
If you have data in vector form, you can use diff() or polyder(). You might actually be able to do:

[yMin I] = min(y)
% corresponding x is:
x(I)

Symbolically, you can use diff() and then solve().

@manyoolo:
"hold on" will allow multiple data to be plotted on the same plot.[/QUO

Dear
This is what I have
h=4.14*10^-15;%eV.s
c=3*10^8%m/s^2
d=124.38*10^-9%m;
lambda= (W50)*10^-9%m
T=T50./100;
y=-(log(T));
alpha=y*(1/d);
nu=(1./lambda).*c;
A=nu.*(alpha).*(h);
D=sqrt(A)
B=nu.*(h);
%plot (B,D, 'om')

hold on
h=4.14*10^-15;%eV.s
c=3*10^8%m/s^2
d=93.06*10^-9%m;
lambda= (W47)*10^-9%m
T=T47./100;
y=-(log(T));
alpha=y*(1/d);
nu=(1./lambda).*c;
A=nu.*(alpha).*(h);
D=sqrt(A)
B=nu.*(h);
%plot (B,D, 'og')

this programs give me good plots in single xy plane
AND my goal is to write only one program in which the program will be able to go and pick the data series ie (W50,T50), (W47, T47)...and plot the graphs without necessarily repeat writing the program for each data series
Hope you got my point

 

[viscousflow]

this programs give me good plots in single xy plane
AND my goal is to write only one program in which the program will be able to go and pick the data series ie (W50,T50), (W47, T47)...and plot the graphs without necessarily repeat writing the program for each data series
Hope you got my point

Use a for loop and place hold off at the end.