On Sat, Mar 27, 2021 at 7:56 PM Matthew Redmayne <30203333@blackpool.ac.uk> wrote:
Hello,
I receive the following error when attempting a simple laplace transform, any idea on why it is happening?
Regards,
Matt
If you do:
yms t x
f= 10*t^3*cos(15*t);
laplace (f,x)
f= 10*t^3*cos(15*t);
laplace (f,x)
then octave gives:
ans = (sym)
⎛ 4 2 ⎞
60⋅⎝x - 1350⋅x + 50625⎠
─────────────────────────────────
2
⎛ 2 ⎞ ⎛ 4 2 ⎞
⎝x + 225⎠ ⋅⎝x + 450⋅x + 50625⎠
⎛ 4 2 ⎞
60⋅⎝x - 1350⋅x + 50625⎠
─────────────────────────────────
2
⎛ 2 ⎞ ⎛ 4 2 ⎞
⎝x + 225⎠ ⋅⎝x + 450⋅x + 50625⎠
So Octave symbolic does not like the phase shift!
Maxima gives:
laplace(%10*t^3*cos(15*t+120), t, s);
10*((6*cos(120))/(s^2+225)^2-(24*cos(120)*s^2)/(s^2+225)^3-(24*s*(cos(120)*s-15*sin(120)))/(s^2+225)^3+(48*s^3*(cos(120)*s-15*sin(120)))/(s^2+225)^4)