Solving a equation from excel.

Hello everyone,

I am trying to solve a equation and integration from a excel data. But I am getting an error in solving the equation.

The equation is (according to excel namings): XD60^2+U_prime^2-{(V_prime^2+W_prime^2)/2}.

This equation i need to integrate. Can someone help me in solving this. I have tried using the following code is as follows

[num data raw] = xlsread('Matlab_trail.xlsx');
for i=1:size(num,2)
    %     Num{i} = num(:,i)(~isnan(num(:,i)));
    Col = num(:,i);
    Num{i} = Col(~isnan(Col));
end
A1 = pi*Num{1}.^2*1.225;
Q1 = A1.*Num{2}.^2;
Int1 = cumtrapz(A1, Num{2}.^2);

A2 = 2*pi*1.225*Num{3};
Q1 = Num{2}.^2+Num{4}.^2-{Num{6}.^2+Num{8}.^2}./2;
Int2 = cumtrapz(A2, Q1);
plot(Num{1}, Int1, 'linewidth', 2);
hold on 
plot(num(:,1), Int2, 'linewidth', 2);
hold off

Answer 1

[dpb]

Going at it hard way...first, just read the data as a table and can keep the variables as identified already...

>> tTrail=readtable('Matlab_trail.xlsx');
>> head(tTrail,3)
ans =
  3×8 table
        R          XD60        XD        U_prime      XD_1       V_prime       XD_2       W_prime
    __________    ______    _________    _______    _________    _______    __________    _______
             0    2.6909            0    0.24286    0.0015318    0.18446    0.00030059    0.18852
    0.00038442    2.6851    0.0040551    0.24391     0.005111    0.18542     0.0038698    0.18833
     0.0017053    2.6794    0.0076322    0.24468    0.0086903    0.18591     0.0074389    0.18858
>> 

Then, use MATLAB vector syntax...

tTrail.Eqn=tTrail.XD60.^2+U_prime.^2-(V_prime.^2+W_prime.^2)/2;

Follow on with the next steps as you know the values you're trying to compute better than we can read the (nonworking) code.

NOTA BENE:

The expression

tTrail.XD60.^2+U_prime.^2

can also be written as

hypot(tTrail.XD60,U_prime).^2

[Vishnuvardhan Naidu Tanga]

Hello @dpb

Thank you for the reply. I have tried the equation but I am getting an error stating "Unrecognized function or variable 'U_prime'."

[dpb]

What does the result of head(tTrail,3) like I showed above return? It worked as shown here with the sample file.

Post the code as you ran it and the error in context; SOMETHING is different, but we can't see what...

[Vishnuvardhan Naidu Tanga]

Hello @dpb

i have found an other way to do the equation. Thank you for the help.