fzero of function 3 variables
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function dydt = eqdiff(t,y,lambda)
dydt=-lambda*y
lambda=1
I write
fzero( @eqdiff(t,y,lambda),2)
matlab give me errore message
how i can solve the zero of a function
4 个评论
Torsten
2020-4-9
Could you clearly state the problem you are trying to solve ?
raffaele orlando
2020-4-9
Torsten
2020-4-9
So in the simple case you stated, you want to know for which value of y the expression -lambda*y becomes zero ?
raffaele orlando
2020-4-9
采纳的回答
Ameer Hamza
2020-4-9
To solve the equation with multiple input variables, use fsolve. Also, the input can be multi-dimensional, but the variable needs to be the same. For example
fsolve(@(x) eqdiff(x(1),x(2),x(3)), zeros(1,3))
function dydt = eqdiff(t,y,lambda)
dydt=-lambda*y;
lambda=1;
end
更多回答（1 个）
Walter Roberson
2020-4-9
fzero() is designed for single functions of one variables that return scalar values.
fsolve() from the Optimization toolbox can handle multiple variables (and multiple functions.)
Sometimes what you can get away with is
fminunc( @(tyl) eqdiff(tyl(1), tyl(2), tyl(3)).^2, initial_values)
However,
function dydt = eqdiff(t,y,lambda)
dydt=-lambda*y
lambda=1
That last line confuses me. You have lambda on input but you assign 1 to it inside the function? What are you expecting that would do for you?
I suspect that you are using the wrong approach to what you are doing. I suspect that you are trying to solve a boundary value problem; see https://www.mathworks.com/help/matlab/boundary-value-problems.html for those.
Your function has trivial solutions: just let y or lambda be 0.
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