Please help how to plot theta vs z in this equation . . . .

e=8.85*10^-12
dele=11
E=1
k11=9
k33=10
k22=11
syms theta(z) z
dtheta=diff(theta,z)
d2theta=diff(theta,z,2)
eqn=d2theta+((k33-k11)*cos(theta)*sin(theta))*(dtheta)^2*(1/(k11*(cos(theta))^2+k22*(sin(theta))^2))+e*dele*E^2*cos(theta)*sin(theta)
thetaSol = dsolve(eqn);

I am unable to get how to plot theta vs z, kindely guide how to proceed furtherThis is the original equation kindely help to plot theta vs z

[Torsten]

You have to specify two boundary conditions for theta to fix a solution. Otherwise, only theta = 0 will be returned from "dsolve".

Having done this, I suppose "dsolve" will not be able to give a solution.

Try ODE45 on the system (theta = y1, theta' = y2)

y1' = y2
y2' = (-e*dele*E^2*sin(y1)*cos(y1)-(K33-K11)*sin(y(1)*cos(y1)*y2^2)/(K11*cos(y1)^2+K22*sin(y1)^2)

Answer 1

[Walter Roberson]

fplot(thetasol, [minz, maxz])

However... matlab says thetasol = 0 which is a boring plot