# Output matrix for simple function

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Derek on 14 Apr 2014
Commented: Evangelia Lo on 12 Nov 2021 at 18:37
I'm brand new to Matlab, and have created a very simple function here to calculate an ion's equilibrium potential:
function y = equipotent(n,X1,X2)
y = (58/n) * log10(X1/X2);
I'd like to do two things: 1) vary X2 for a set of values (1-100) while keeping X1 and n constant. and 2) store all the outputs from the function in a vector for plotting X2 vs y.
Anything helps! Thanks!

the cyclist on 14 Apr 2014
If you change your code to
function y = equipotent(n,X1,X2)
y = (58/n) * log10(X1./X2);
then it will give a vector output y for vector input X2, and you should be all set.

Sven on 14 Apr 2014
Hi Derek,
MATLAB has some useful ways to do what you're trying to do. If you use the (.*) operator instead of (*), it will perform a vector multiplication.
function y = equipotent(n,X1,X2)
y = (58 ./ n) .* log10(X1 ./ X2);
Then you can just run commands:
y = equipotent(4, 3, X2)
figure
plot(X2,y)
Evangelia Lo on 12 Nov 2021 at 18:37
The type of function is