Code to input function
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I want to make a code where user can input the the function and as the output they get plot of f(x) vs x and also the roots of that non linear equation.
回答（2 个）
David Hill
2022-8-29
Plotting would not be a problem, but finding all the roots is a problem. Recommend looking at fzero
a=input('Function (example: @(x)x.*cos(x)-x.^2.*sin(x)+exp(-x)): ','s');
f=str2func(a);
x=-pi:.001:2*pi;
plot(x,f(x));
% fstr = input("Key in a function of x (eg. x.^2 + 2*x - 1): ", "s")
fstr = "@(x) x.^2 + 2*x - 1"; % This is for on-line matlab
try
% eval("f = "+ fstr )
f = str2func(fstr)
fplot(f)
x1 = fzero(f, 0)
title(fstr + ": x1="+x1)
end
1 个评论
Walter Roberson
2022-8-29
Do not use eval for this purpose, use str2func()
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