# i have function L and initial values phi1 ,phi2 and seta . I want to be derivative this function and equal it by zero for getting the estimated values of these initial values. but showing the next error .what to do?

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mohammed elmenshawy am 23 Dez. 2016
Bearbeitet: John D'Errico am 27 Dez. 2016
syms phi1 phi2 seta
L=- ((38*phi1)/281 - (89*phi2)/902 + (149*seta)/1124 - 83/28)^2/8; % function
phi1=0.3; % initial point
phi2=0.5; % initial point
seta=0.4; % initial point
phi1hat=fzero(L,phi1);
phi2hat=fzero(L,phi2);
setahat=fzero(L,seta);
Error using fzero (line 167)
If FUN is a MATLAB object, it must have an feval method.
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mohammed elmenshawy am 24 Dez. 2016
A summary of what I want to do . i have function of 3 parameters L=f(phi1,phi2,seta). i need differential this function with respect to phi1 , phi2 and seta , and equality to zero. Hence we get three equations in three parameters , Give initial values of the three parameters.In the first equation, which is where the differentiation for phi1 we substitute only about phi2 and seta to get phi1 value . By this logic with the phi2 and seta . what to do ?
John D'Errico am 27 Dez. 2016
Bearbeitet: John D'Errico am 27 Dez. 2016
Note that you were trying to solve a 3-dimensional problem, by calling fzero, a 1-d solver, three times. Sorry, but that makes no sense. Use fsolve preferentially, or lacking that, you can use fminsearch if used properly.

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