ode: 'diff(y(t), t, 2) + 5*'diff(y(t), t) + 4*y(t) = t;
2 d d --- (y(t)) + 5 (-- (y(t))) + 4 y(t) = t 2 dt dt
ode2(ode, y(t), t);
- t - 4 t 4 t - 5 y(t) = %k1 %e + %k2 %e + ------- 16
sol: ic2(%o2, t=0, y(t)=0, 'diff(y(t), t) = 0);
- t - 4 t (4 y(0) + 1) %e (16 y(0) + 1) %e 4 t - 5 y(t) = ------------------ - --------------------- + ------- 3 48 16
This result is still not entirely satisfying; the value of y(0) should be zero. We use substitution to further simplify:
%, y(0)=0;
- t - 4 t %e %e 4 t - 5 y = ----- - ------- + ------- 3 48 16
It is also possible to use a simpler notation with ode2:
eq: 'diff(y, x, 2) + 5*'diff(y,x) + 4*y = x;
2 d y dy --- + 5 -- + 4 y = x 2 dx dx
ode2(eq, y, x);
- x - 4 x 4 x - 5 y = %k1 %e + %k2 %e + ------- 16
sol: ic2(%, x=0, y=0, 'diff(x, y) = 0);
- x - 4 x %e %e 4 x - 5 y = ----- - ------- + ------- 3 48 16
The availability of different notations is a frequent source of confusion. We remember: