Bug introduced in 12.2(?), persisting through 14.0 or later.
When I am solving odes using LaplaceTransform, I found that LaplaceTransform works well with u[t] or y[t] or x[t], but doesn't recognize x[1][t].
So, how to make LaplaceTransform know x[1][t]?
Thanks.
In[125]:= LaplaceTransform[a x[t] + b y'[t], t, s] // Simplify
Out[125]=
a LaplaceTransform[x[t], t, s] + b s LaplaceTransform[y[t], t, s] -
b y[0]
In[126]:= LaplaceTransform[a x[1][t] + b x[2]'[t], t, s] // Simplify
Out[126]= LaplaceTransform[a x[1][t] + b Derivative[1][x[2]][t], t, s]

LaplaceTransform[#, t, s] & /@ (a x[1][t] + b x[2]'[t]). – Mariusz Iwaniuk Jan 06 '22 at 15:36