How to Input a function equation in matlab

Hi, I have an equation as following:

F - hm*(a-b)*log(1+F/(hm*(a-b))) = kt

I am trying to use fzero to solve for F in matlab, but I don't know how to input this equation in matlab first?

[KALYAN ACHARJYA]

Share what you have done so far?

[KSSV]

Read the documentation.....it got lot of example.....MATLAB is rich in documentation.

[Ivy Shen]

I am trying to write a function as following:

function F = GreenAmp(Ks,hm,t,a,b)

F - hm*(a-b)*log(1 + F/(hm*(a-b))) = Ks*t;

And I don't know what's the next step. Is there any easier way to do it? Can you specify which documentation I should look at?

Thank you.

[Stephen23]

function F = GreenAmp(Ks,hm,t,a,b)
F - hm*(a-b)*log(1 + F/(hm*(a-b))) = Ks*t;

That will not work:

• variable F is used but undefined. In order to solve for F, F must be one of the input arguments to the function.
• the LHS of the = sign is not valid for assignment: the LHS should be one variable, which is the value of the function when it is evaluated.

"Can you specify which documentation I should look at?"

https://www.mathworks.com/help/matlab/getting-started-with-matlab.html

https://www.mathworks.com/help/matlab/ref/function.html

https://www.mathworks.com/help/matlab/math/parameterizing-functions.html

https://www.mathworks.com/help/matlab/ref/fzero.html

Answer 1

[Stephen23]

>> b = 1;
>> a = 2;
>> hm = 0.5;
>> kt = 0.9;
>> fun = @(F) F - hm*(a-b)*log(1+F/(hm*(a-b)));
>> y = fzero(@(x)fun(x)-kt,0)
y =  1.6230
>> fun(y)
ans =  0.90000

Note that this curve might have multiple solutions, depending on the parameter values: fzero only finds one solution, so you will have to adjust its starting value to find any other solutions. You should always plot the curve and check if the solution is reasonable:

X = -10:0.1:10;
Y = arrayfun(fun,X);
plot(X,Y)
hold on
plot(y,0.9,'*')

[KSSV]

I have deleted my answer..which was ridiculous.