[HP50G] DESOLVE Error: Bad Argument Type

[peacecalc]

Hello dns.olic,

I keyed in:

1. 'd1d1y(t)=2*COS(t/2)-5*y(t)'
2. 'y(t)'

And use DESOLVE and I get a result with the two constants cC0 and cC1.

If I key in 'd1d1y(t)+5*y(t)=2*COS(t/2)' and not 'd1d1y(t)=2*COS(t/2)-5*y(t)', I although get an error message.

Same procedure with constrains, same behavior DESOLVE works with:
[ 'd1d1y(t)=2*COS(t/2)-5*y(t)' 'y(0)=6/5' 'd1y(0)=-1/2'] + ENTER
2. 'y(t)'