how to write a formula in matlab including different variation
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hey guys im new in matlab i try to write a fourmula with some variation in matlab but as i said im so new here. could you please help me with
A= EXP^ (PI/3)* R/X
THATS A PART OF FORMULA here r has difrent value
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Accepted Answer
Star Strider
on 6 Oct 2019
First:
A = exp(pi/3)*r./x; % Statement
A = @(r) exp(pi/3)*r./x; % Anonymous Function
3 Comments
Star Strider
on 6 Oct 2019
As always, my pleasure.
I am not certain what you are asking. Taking a guess:
Out = -R.*V.*(1+A(R)).^2)./(3*X.^2)
You left out several operators that I assume are implicit multiplication, so I used the vectorised multiplication operator (.*), and vectorised the rest of that expression as well (.^, ./).
Note that:
V(1+A)
will otherwise be interpreted as the (1+A) element of the V vector, and that will only work if A(R) returns an integer value >=0.
More Answers (5)
moji abb
on 6 Oct 2019
13 Comments
Star Strider
on 8 Oct 2019
Again, my pleasure.
Please code the equation, and post the code back here. It would be helpful if you also include the values of the variables.
moji abb
on 10 Oct 2019
2 Comments
Star Strider
on 10 Oct 2019
I made a few small changes to get your code to run with different values of ‘X’ as well as different values of ‘R’. This involves adding a loop and changing some of the indexing.
Your code is otherwise essentially unchanged:
%%% ====== input values =========
U = 12;
% R = 2; % change from R=0,1,2,3
L = [2200e-6; 2.9e-3; 3.8e-3]; % change from 0.0022 to 0.0045 in mH
frequency = 400; % in Hz, maybe 50Hz.
fi = pi/3;
Er = 8;
ksi = 0.1;
Xv = 2*pi*frequency*L; % ‘X’ is now vector ‘Xv’
r = [];
y = [];
Rv = 0:0.1:3; % ‘R’ is now vector ‘Rv’
figure
hold all
for k1 = 1:numel(Xv)
X = Xv(k1); % ‘X’ is an element of ‘Xv’ in each loop iteration
for k2 = 1:numel(Rv)
R = Rv(k2);
r(k1,k2) = R;
a = exp((R/X)*(pi/3));
k = R/X;
alfa = atan(X/R);
alfa1 = alfa*0.017;
output = -R*U*(1+a)^2*exp(-k*(fi-pi/3))/(3*X^2*(1+a^3))+Er*sin(fi-ksi-alfa1)/sqrt(R^2+X^2);
y(k1,k2) = output;
end
plot (r(k1,:), y(k1,:))
OutpLeg{k1} = sprintf('Output L = %.1f mH', L(k1)*1000);
end
hold off
legend(OutpLeg)
xlabel('R'), ylabel('output')
title('gragh R\_output')
Experiment to get the result you want.
moji abb
on 10 Oct 2019
7 Comments
Star Strider
on 15 Oct 2019
I am having a very difficult time understanding what you want to do.
Apparently, you need to re-arrange your equations for your dependent variable as a function of ‘L’ as the independent variable. The easiest way to do this is to use the Symbolic Math Toolbox.
I cannot do that for you because I do not understand your equations or what you want to do with them.
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