How can ı solve invalid indexing or function
3 vues (au cours des 30 derniers jours)
Afficher commentaires plus anciens
I have an error. how can I solve?
Invalid indexing or function definition. Indexing must follow
MATLAB indexing. Function arguments must be symbolic variables,
and function body must be sym expression.
clc;
clear all;
syms nw W x Q(x) Y Qo
ode1=diff(Q,x)== -nw*W*Y;
cond1 = Q(0)== 0;
cozum1(x)=dsolve(ode1,cond1);
cozum1=simplify(cozum1(x))
syms d W nu P(x) Q
ode2=diff(P,x) == -Q*((3*nu)/(W*2*d.^3));
cond2(x)= P(0)==0;
cozum2(x)=dsolve(ode2,cond2);
cozum2=simplify(cozum2(x))
syms Yx f Po Pref f5 Q Q1 H R W d Pinf lamdac a b Qref s
f1=P(x)-Po==(-3*nu*Q*x)./(2*W*(d.^3)) ;%cozum2=Px-Po
f2=P(x)-Pinf == nu*H*Y/R; %(denklem1=Px-Pinf it is given)
%(P-Po)==(P-Pinf)===>we accepted
a1=(-3*nu*Q*x)/(2*W*(d.^3))== (nu*H*Y/R);
a2=subs(a1,Q,(cozum1))
lamdac=isolate(a2,x) % =====> x equal to characteristic lenght (lamdac)
a4=isolate(a1,Q); % Q(x)= -H*W*(d^3)*R*Y*2/3*R*nu*x (Q(x) is left alone in the above equation a1)
Q(x)= -H*W*(d^3)*Y*2/3*R*x ;
a5=subs(a4,H*Y./R,(Po-Pinf)); %If we substitute the value of (Po-Pinf) in the above equation
Qref=subs(a5,x,lamdac) %=====> Qref
Yx=(Qo/(-nw*W*x)); % from cozum1
Pref=subs(f2,Y,Yx)
Pref == subs(Pref,x,lamdac) %=====> Pref
syms nu H R d W nw Y(x) Q(x) P(x) Pinf s A B C
P(x)=Pinf+(A*Y(x));
dP=diff(P(x),x);
dP==A*Y(x)
dQ=diff(Q(x),x);
dY=diff(Y(x),x);
eqn1=dY+((B/A)*Q)==0
eqn2=dQ+C*Y==0
solLT1=laplace(eqn1,x,s)
solLT2=laplace(eqn2,x,s)
syms Y_LT Q_LT U V Yave L Y_ave
solLT1=subs(solLT1,[laplace(Y(x),x,s) laplace(Q(x),x,s)],[Y_LT Q_LT]);
solLT2=subs(solLT2,[laplace(Y(x),x,s) laplace(Q(x),x,s)],[Y_LT Q_LT]);
solLT1=subs(solLT1,[Y_LT Q_LT],[U V])
solLT2=subs(solLT2,[Y_LT Q_LT],[U V])
%Cramer Rule
Y(0)==(U*s)+(B/A)*V;
Q(0)==U*C+(s*V) ;
A1=[s (B/A);
C s ];
A2=[Y(0), (B/A) ;
Q(0),s];
A3=[s (B/A);
C s;];
detA2=det(A2);
detA3=det(A3);
U=(detA2/detA3)
B1=[s,Y(0);
C,Q(0);];
detB1=det(B1)
V=(detB1/detA3)
Y=ilaplace(U,s,x)
eqnY=subs(Y,[A B C], [(nu.*H./R) (3.*nu./(2*d.^3.*W)) (nw.*W)])
eqnY1=subs(eqnY, ((2.*d.^3.*H)./(3.*nw.*R)).^0.5,lamdac)
Q=ilaplace(V,s,x)
eqnQ=subs(Q, [A B C], [(nu.*H./R) (3.*nu./(2*d.^3.*W)) (nw.*W)])
eqnQ1=subs(eqnQ, ((2.*d.^3.*H)./(3.*nw.*R)).^0.5,lamdac)
%f2=P(x)-Pinf== nu*H*Y(x)/R ====> Y=eqnY1
P(x)=Pinf+ (nu*H.*Y(x)./R)
P(x)==subs(P(x),Y(x),eqnY1)
0 commentaires
Réponses (1)
VBBV
le 17 Jan 2022
Modifié(e) : VBBV
le 17 Jan 2022
clc;
clear all;
syms nw W x Q(x) Y Qo
ode1=diff(Q,x)== -nw*W*Y;
cond1 = Q(0)== 0;
cozum1(x)=dsolve(ode1,cond1);
cozum1=simplify(cozum1(x))
syms d W nu P(x) Q
ode2=diff(P,x) == -Q*((3*nu)/(W*2*d.^3));
cond2(x)= P(0)==0;
cozum2(x)=dsolve(ode2,cond2);
cozum2=simplify(cozum2(x))
syms Yx f Po Pref f5 Q Q1 H R W d Pinf lamdac a b Qref s
f1=P(x)-Po==(-3*nu*Q*x)./(2*W*(d.^3)) ;%cozum2=Px-Po
f2=P(x)-Pinf == nu*H*Y/R; %(denklem1=Px-Pinf it is given)
%(P-Po)==(P-Pinf)===>we accepted
a1=(-3*nu*Q*x)/(2*W*(d.^3))== (nu*H*Y/R);
a2=subs(a1,Q,(cozum1))
lamdac=isolate(a2,x) % =====> x equal to characteristic lenght (lamdac)
a4=isolate(a1,Q); % Q(x)= -H*W*(d^
Q(x)= -H*W*(d^3)*Y*2/3*R*x ;
a5=subs(a4,H*Y./R,(Po-Pinf)); %If we
Qref=subs(a5,x,lamdac) %=====> Qref
Yx=(Qo/(-nw*W*x)); % from cozum1
Pref=subs(f2,Y,Yx)
Pref == subs(Pref,x,lamdac) %=====> Pref
syms nu H R d W nw Y(x) Q(x) P(x) Pinf s A B C
P(x)=Pinf+(A*Y(x));
dP=diff(P(x),x);
dP==A*Y(x)
dQ=diff(Q(x),x);
dY=diff(Y(x),x);
eqn1=dY+((B/A)*Q)==0
eqn2=dQ+C*Y==0
solLT1=laplace(eqn1,x,s)
solLT2=laplace(eqn2,x,s)
syms Y_LT Q_LT U V Yave L Y_ave
solLT1=subs(solLT1,[laplace(Y(x),x,s) laplace(Q(x),x,s)],[Y_LT Q_LT]);
solLT2=subs(solLT2,[laplace(Y(x),x,s) laplace(Q(x),x,s)],[Y_LT Q_LT]);
solLT1=subs(solLT1,[Y_LT Q_LT],[U V])
solLT2=subs(solLT2,[Y_LT Q_LT],[U V])
%Cramer Rule
Y(0)==(U*s)+(B/A)*V;
Q(0)==U*C+(s*V) ;
A1=[s (B/A);
C s ];
A2=[Y(0), (B/A) ;
Q(0),s];
A3=[s (B/A);
C s;];
detA2=det(A2);
detA3=det(A3);
U=(detA2/detA3)
B1=[s,Y(0);
C,Q(0);];
detB1=det(B1)
V=(detB1/detA3)
Y(x)=ilaplace(U,s,x); % change this line
eqnY=subs(Y(x),[A B C], [(nu.*H./R) (3.*nu./(2*d.^3.*W)) (nw.*W)])
eqnY1=subs(eqnY, ((2.*d.^3.*H)./(3.*nw.*R)).^0.5,lamdac)
Q=ilaplace(V,s,x)
eqnQ=subs(Q, [A B C], [(nu.*H./R) (3.*nu./(2*d.^3.*W)) (nw.*W)])
eqnQ1=subs(eqnQ, ((2.*d.^3.*H)./(3.*nw.*R)).^0.5,lamdac)
%f2=P(x)-Pinf== nu*H*Y(x)/R ====> Y=eqnY1
P(x)=Pinf+ (nu*H.*Y(x)./R)
P(x)==subs(P(x),Y(x),eqnY1)
Check with this
0 commentaires
Voir également
Catégories
En savoir plus sur Calculus dans Help Center et File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!