Summing a series within a For Loop

H = 0.1;

I = 5;

Y = 0;

BI = zeros(I,1);

for i = 1:I

b = fzero(@(b)(b*tan(b)-H),pi*i);

BI(i) = b ;

end

X = linspace(0,1,I);

Theta = zeros(I,1);

for k = 1:length(X)

for m = 1:BI

Ts = sum(((((1/BI).*(1-cos(BI)))/(0.5-(1/(4.*BI)))).*sin(BI.*Y).*(cosh(2.*BI.*(X))-tanh(2.*BI).*sinh(2.*BI.*(X)))));

end

end

I'd like to:

• Start at X =0
• Sum Ts for all values of BI
• Step to next value of X
• Sum Ts for all values of BI
• etc.

Answer 1

[Edoardo_a]

Hi, do you mean something like that?

In this case I sum all the values in the same Ts variable for all the X entry.

If you want to save a different Ts sum for each X entry then you should preallocate and store each Ts from the for loop.

H = 0.1; 
I = 5;
Y = 1; 
       
BI = zeros(I,1);
for i = 1:I
      b = fzero(@(b)(b*tan(b)-H),pi*i);
      BI(i) = b ;
end
X = linspace(0,1,I); 
Theta = zeros(I,1);
Ts = zeros(1);
for k = 1:length(X)
    for m = 1:length(BI) 
    Ts =Ts + ((((1/BI(m)).*(1-cos(BI(m))))/(0.5-(1/(4.*BI(m))))).*sin(BI(m).*Y).*(cosh(2.*BI(m).*(X(k)))-tanh(2.*BI(m)).*sinh(2.*BI(m).*(X(k)))));
    end
end

[VBBV]

H = 0.1; 
I = 5;
Y = 1; 
       
BI = zeros(I,1);
for i = 1:I
      b = fzero(@(b)(b*tan(b)-H),pi*i);
      BI(i) = b ;
end
X = linspace(0,1,I); 
Theta = zeros(I,1);
Ts = zeros(1);
for k = 1:length(X)
    for m = 1:length(BI) 
       Ts(m) = ((((1/BI(m)).*(1-cos(BI(m)*pi/180)))/(0.5-(1/(4.*BI(m))))).*sin(BI(m)*(pi/180).*Y).*(cosh(2.*BI(m)*(pi/180).*(X(k)))-tanh(2.*BI(m)*pi/180).*sinh(2.*BI(m)*(pi/180).*(X(k)))));
                                        %->>
    end
    TS(k) = sum(Ts);
end
TS

TS = 1×5

0.0030 0.0029 0.0028 0.0027 0.0027

You can do store the Ts values for each BI iteration using its index, and sum the Ts variable later. Also, input values to trigonometric functions, need to be in radians, for which you can multply with pi/180