[Solved] Find the value of a variable

Hi. I'm still new using matlab and struggling with a portion of my code. In this phase I need to find the value of a certain variable(s) present in an equation/array. I read about fsolve but it needs to be in a script since I can't do them one by one (and from what I read, I don't think this code can work that way). I would be thankful if someone could help me solve this problem. I only have one variable but if possible I would like to know how to do with more than one.

Thank you in advanced.

example 1 (I want to find x):

f(1)=34;
f(2)=12;
for k=1:2;
  x(k,1)^2+3*x(k,2)+4=f(k); %what I want to solve
end

example 2 (I want to find A and B):

g(1,1)=34;
g(1,2)=12;
g(2,1)=100;
g(2,2)=156;
for k=1:2;
   A=[4 3; 1 2]*[A(k); B(k)]=[g(k,1); f(k,2)];
end

[Lucas Neves]

Pedro, are you sure this code is complete? I mean, when you say i=1,10 then x=2 you will get x=2 and not =x-2... I'm not getting this clearly but is that all the code? Cheers

[Pedro Pires]

Thank you for the message. You're right. This isn't my code but I wanted to keep it simple so I made these. Didn't look carefully enough and made some mistakes. I think that they have been corrected.

Edit: I solved the problem already. I tried to use solve() before but wasn't able to run it because i didn't use the syms command.

Answer 1

[Image Analyst]

the syntax is not right. Perhaps you meant

for i = 1 : 100

or better yet, use k instead of i, which is the imaginary variable.

Regarding "find x":

Similar for finding A and B.

This line of code has bad syntax with two equal signs.

A=[4 3; 1 2]*[A; B]=[0; 0];

I have no idea what you're attempting. And in both of the loops, there is no change of anything inside as the loop iterates so I don't know what the loop is for.

Answer 2

[Pedro Pires]

Ahah. Thank you for the answer either way. I think the mistakes have been corrected.