how to solve the nonlinear equatios?

Question

M.Rameswari Sudha 2020-1-2

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/498648-how-to-solve-the-nonlinear-equatios

评论： VBBV 2024-3-7

syms T v 
p=30;a=7;d=1;lamda=0.8;c=10;r=35;h=0.05;w=200;k=0.02;b=7;
M=k*a;
%eqn1=(1/T)*(p*d-((lamda*p*d*v)/T)-(d*exp(-(w-k)*v)-(d*v/T))*c-d*((v/T)-1)*r-(d/(w-k))*(1-exp(-(w-k)*v)*h)))==0'
%eqn2=((1/T)*(-(d*c*v*exp(-(w-k)*v)*M/(w-k))+(((d*c*(1-exp(-(w-k)*v))+h*d*v*(1+exp(-(w-k)*v)))*M)/(w-k)^2)+((2*h*d*(exp(-(w-k)*v)-1)*M)/(w-k)^3)-1))== 0
eqns = solve('((1/T)*(p*d-((lamda*p*d*v)/T)-(d*exp(-(w-k)*v)-(d*v/T))*c-d*((v/T)-1)*r-(d/(w-k))*(1-exp(-(w-k)*v)*h)))==0','((1/T)*(-(d*c*v*exp(-(w-k)*v)*M/(w-k))+(((d*c*(1-exp(-(w-k)*v))+h*d*v*(1+exp(-(w-k)*v)))*M)/(w-k)^2)+((2*h*d*(exp(-(w-k)*v)-1)*M)/(w-k)^3)-1))== 0');
solve(eqns,T,v)

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KSSV 2020-1-2

YOu cannot use solve at the step eqns = . What are the equations exactly? Can you explain the problem.

M.Rameswari Sudha 2020-1-2

编辑：M.Rameswari Sudha 2020-1-2

I have two equations equation1 & equation2. I couldn't find the value of T and v.

p=30;d=1;lamda=0.8;c=10;r=35;h=0.05;chi=200;k=0.02;b=7;a =0.01;

W= k*(1-exp(-a*chi));

M=k*a;

equation1=(1/T)*[(p*d-((lamda*p*d*v)/T)-(d*exp(-(w-k)*v)-(d*v/T))*c-d*((v/T)-1)*r-(d/(w-k))*(1-exp(-(w-k)*v)*h))]=0

equation2=(1/T)*[-(d*c*v*exp(-(w-k)*v)*M/(w-k))+(((d*c*(1-exp(-(w-k)*v))+h*d*v*(1+exp(-(w-k)*v)))*M)/(w-k)^2)+((2*h*d*(exp(-(w-k)*v)-1)*M)/(w-k)^3)-1]= 0

solve equation1 and equation2 and find the value of T and v from equation1 and equation2

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Answer 1

KSSV 2020-1-2

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/498648-how-to-solve-the-nonlinear-equatios#answer_408406

在 MATLAB Online 中打开

Try this.

syms v T
p=30;d=1;lamda=0.8;c=10;r=35;h=0.05;chi=200;k=0.02;b=7;a =0.01;
w = k*(1-exp(-a*chi));
M=k*a;
equation1=(1/T)*[(p*d-((lamda*p*d*v)/T)-(d*exp(-(w-k)*v)-(d*v/T))*c-d*((v/T)-1)*r-(d/(w-k))*(1-exp(-(w-k)*v)*h))]==0 ;
equation2=(1/T)*[-(d*c*v*exp(-(w-k)*v)*M/(w-k))+(((d*c*(1-exp(-(w-k)*v))+h*d*v*(1+exp(-(w-k)*v)))*M)/(w-k)^2)+((2*h*d*(exp(-(w-k)*v)-1)*M)/(w-k)^3)-1]== 0 ;
eqns = [equation1, equation2] ; 
S = solve(eqns,[ T v]) ; 

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M.Rameswari Sudha 2020-1-2

Again I get the same problem. I got the output as S =

[ empty sym ]

VBBV 2024-3-7

在 MATLAB Online 中打开

syms v T
p=30;d=1;lamda=0.8;c=10;r=35;h=0.05;chi=200;k=0.02;b=7;a =0.01;
w = k*(1-exp(-a*chi));
M=k*a;
equation1=(1/T)*[(p*d-((lamda*p*d*v)/T)-(d*exp(-(w-k)*v)-(d*v/T))*c-d*((v/T)-1)*r-(d/(w-k))*(1-exp(-(w-k)*v)*h))]==0 ;
equation2=(1/T)*[-(d*c*v*exp(-(w-k)*v)*M/(w-k))+(((d*c*(1-exp(-(w-k)*v))+h*d*v*(1+exp(-(w-k)*v)))*M)/(w-k)^2)+((2*h*d*(exp(-(w-k)*v)-1)*M)/(w-k)^3)-1]== 0 ;
eqns = [equation1, equation2] ; 
S = vpasolve(eqns,[ T v])  
S = struct with fields:
    T: -2.8001867614296615890192299028898e+35
    v: 94.487666301429982566887966097196