ED Lab 8

https://rextester.com/l/octave_online_compiler

a)
y'' - 6 * y' + 9 * y = e ^ (3 * x)
b)
y'' - 2 * y' + 2 * y = 5 * e ^ (2 * x) * cos(x)
c)
{   y'' - 2 * y' + y = 0
{   y(1) = 1
{   y'(1) = 2

Rezolvare:
pkg load symbolic
syms y(x)
%   a)
dsolve(diff(diff(y(x), x), x) - 6 * diff(y(x), x) + 9 * y - exp(3 * x))
%   inca o metoda pt y''
dsolve(diff(y(x), x, x) - 6 * diff(y(x), x) + 9 * y - exp(3 * x))
%   inca o metoda pt y''
dsolve(diff(y(x), 2) - 6 * diff(y(x), x) + 9 * y - exp(3 * x))

%   b)
dsolve(diff(diff(y(x), x), x) - 2 * diff(y(x), x) + 2 * y - 5 * exp(2 * x) * cos(x))
%   c)
dsolve(diff(y(x), 2) - 2 * diff(y(x), x) + y == 0, y(1) == 1, diff(y(x), x)(1) == 2)
%0  dunno ce e sau ce treb sa ii fac sa mearga
syms y1(x)
y1(x) = x*x*A*exp(3*x)
diff(y1(x),x)
diff(y1(x),2)

solve(diff(y1(x), 2) - 6*diff(y1(x),x) + 9*y1(x) == exp(3*x),A)
%0