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symbolic code with boundary condition

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MINATI
MINATI on 29 Dec 2019
Commented: MINATI on 29 Dec 2019
t = sym('t'); x = sym('x');
a=5;a1=2;xa=0;xb=3;
g = zeros(1,3,'sym');ga = zeros(1,3,'sym');g(1)=a*x+(5/2)*x.^2;
for i=1:3
ga(i) = subs(g(i),x,t);dga = diff(ga(i),t,1);d2ga = diff(dga,t,1);
Ig1 = int(-ga(i)*d2ga + 2*dga,t,0,t);Ig2=int(Ig1,t,0,t);Ig3=int(Ig2,t,0,x);
g(i+1) = a1*Ig3;
% % disp(g(i+1))
end
g = g(1)+g(2)+g(3)+g(4);
G1 = double(subs(g, x, xn));G2 = [a diff(double(subs(g,x,xn)))];
xn=linspace(xa,xb,100);x = xn;
figure(1)
plot(xn,G1,'LineWidth',1.5)
xlabel('\bf\eta'); ylabel('\bfg(\eta)');
hold on
figure(2)
plot(xn,G2,'LineWidth',1.5)
xlabel('\bf\eta'); ylabel('\bfg^''(\eta)');
hold on
%% G1 should start from '1' and G2 from 'a' end with '0' (in Y-axis)
what modification needed?

  3 Comments

KALYAN ACHARJYA
KALYAN ACHARJYA on 29 Dec 2019
Undefined function or variable 'xn'.
MINATI PATRA
MINATI PATRA on 29 Dec 2019
It is defined as linspace in the code
MINATI
MINATI on 29 Dec 2019
G1(0)=0;G2(0)=a;G2(inf)=0;

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