Arithmetic problem with for loop

Hi, i am new with MATLAB.

I would like to use this formula in for loop: ℓ?=taper1*ℓ?−1

There is no error message but i can't see a proper value on output. (i control my values with calculator programs) (i checked my variables. and confirmed that they are true before this loop).

And my second problem is i don't know how to add new line with every increment.

Here is my try:

l= (1:N); //creating and empty array
l(1)=((3*(10^8))/(2*f1)); //formula 
for i = 2:N
    l(i) = taper1 * l(i - 1);
    set(handles.popupmenu3,'String',l(i) );
end

i tried to add new line with this but didn't work

  set(handles.popupmenu3,'String',l(i) \n );

[Rik]

Most of what you have shown here is not valid Matlab syntax. It seems like you lack the basics of Matlab. It is really useful to learn the basics before attempting more complicated things. This even holds true for a relatively simple language as Matlab.

This is one of many tutorials you could try.

Answer 1

[Walter Roberson]

l = zeros(1,N); %creating and empty array
l(1) = ((3*(10^8))/(2*f1)); %formula 
for i = 2:N
    l(i) = taper1 * l(i - 1);
    handles.popupmenu3.String{end+1} = num2str( l(i) );
    drawnow();
end

updating the popup string one by one is inefficient: it would be better to do all of the calculations first and then update at the end.

Note: you could also calculate

l = ((3*(10^8))/(2*f1)) .* taper1.^(0:N-1);

with no loop required.

[Rik]

Shouldn't it be this?

handles.popupmenu3.String{end+1}
%                    ----------^

[Walter Roberson]

You are right, Rik; I have fixed it.

[Mustafa Uysal]

Thank you,it works

And lastly, i would like to write l(i)=value to each line. How can i add l(i)?

[Rik]

Do you mean something like this?

handles.popupmenu3.String{end+1} = sprintf( 'value= %.1f' , l(i) );

[Mustafa Uysal]

Not exactly,

my desired output is: (lets say i=5 and value=3)

l(5)= 3

[Rik]

So like this?

sprintf('l(%d)= %.1f',i,l(i))

Otherwise, try searching the documentation for a solution. Matlab has excellent documentation with many examples.

[Mustafa Uysal]

It works thank you.