Matlab Error: Matrices must agree

Hello,

I am programming the following function:

V = 500;
c2 = 10;

Pv = 1/V;
% IvLin = a1*v; %what is v?
% IvQuad = a2*v^2;
% PDvLin = c2/v; %linear?
% PDvQuad = c2/(v^2); %quad?

%%%%%%Solve for a1 or a2 %%%%%%%
% size(c2)
% size(V)
% size(Pv)

funequ2 = @(v) v*(c2/v)*(1/V);
size(funequ2)
Equation2 = integral(funequ2,0,V);

funequ1 = @(v) (a1*v).*Pv;
Equation1 = integral(funequ1,0,V);%what is the upperbound

syms a1
solve(Equation1 == Equation2

For some reason it is not solving anything because I keep getting the error that the matrices must agree. When I checked the size of my components, they are all the same (1,1). I don't understand what the problem is. Could someone kindly help and provide some insight? This seems like it should have very simple.

Kam

[Jason Ross]

edited and used the code tag for clarity

[PT]

Would it help if you convert all multiplicative operations to element-wise (Use .* and ./ instead of * and /, respectively)?

[Walter Roberson]

You have not shown us a1

[Kam Selley]

Hi Walter,

a1 is my unknown and what I am solving for.

Answer 1

[Youssef Khmou]

hi,

a1 is unknown, but check this solution , although the code technically correct , the solution is empty :

%dbstop if error
V = 500;
c2 = 10;
a1=10;
Pv = 1/V;
funequ1 = @(v) v.*(c2./v)*(1/V);
f1=funequ1(1:0.1:10);
F1 = integral(f1,0.1);

 funequ2 = @(v) (a1*v).*Pv;
f2=funequ2(1:0.1:10);
F2=integral(f2,0.1);

 solve(F1 == F2)

[Kam Selley]

Hello,

I am trying to solve for a1 so that is why a1 is not defined.

[Youssef Khmou]

In this case then :

 SOL=solve('v*(c2/v)*(1/V)-(a1*v)*Pv=0','a1');
 >> SOL

 SOL =

 c2/V/v/Pv

a1=c2/V/v/Pv

[Kam Selley]

I am not sure I can follow what you actually did. Did you just solve the integrals yourself instead of letting matlab do it. The error for your above answer says there's not enough input arguments.