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solving non linear equation

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RAFFAELE CANTERI
RAFFAELE CANTERI 2020 年 10 月 12 日
コメント済み: Star Strider 2020 年 10 月 13 日
how can i return a vector as a solution?
I want back a number of roots equal to the number of values ​​of t
syms S
>> myfun = @(S,t) 0.17*((S/10.8)+(S/21.6*sqrt(1+16*((S/5.4)^2))+((1/16)*log((4*S/5.4)+sqrt(1+(16*(S/5.4)^2))))))- t
>> t = linspace(0,2.6,10)
>> fun = @(S) myfun(S,t)
S = fzero(fun,0.03)
The program return this error:
Operands to the || and && operators must be convertible to logical scalar values.
Error in fzero (line 327)
elseif ~isfinite(fx) || ~isreal(fx)

採用された回答

Star Strider
Star Strider 2020 年 10 月 12 日
First:
vv = vectorize('0.17*((S/10.8)+(S/21.6*sqrt(1+16*((S/5.4)^2))+((1/16)*log((4*S/5.4)+sqrt(1+(16*(S/5.4)^2))))))- t')
then copy the result (between the single quotes) to the body of ‘myfun’.
After that (I have already done and copied the vectorized result):
myfun = @(S,t) 0.17.*((S./10.8)+(S./21.6.*sqrt(1+16.*((S./5.4).^2))+((1./16).*log((4.*S./5.4)+sqrt(1+(16.*(S./5.4).^2))))))- t;
t = linspace(0,2.6,10)
for k = 1:numel(t)
S(k) = fzero(@(S) myfun(S,t(k)),0.03);
end
and you get the result you want.
  2 件のコメント
Star Strider
Star Strider 2020 年 10 月 13 日
As always, my pleasure!

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