Inverse Laplace to time domain graphing

Thread Starter

Nathan Hale

Joined Oct 28, 2011
Hello All and hope all of you are doing great!
I have a question regarding basic control systems.
So i have a transfer function, which is 1 / (s^2 +9s +20) whose inverse Laplace ends up being ( e^-4t) - ( e ^-5t).
Here is my question:
When I designed the transfer function in MATLAB, the output of the scope is as shown below ( with the black background).
When I graphed the Inverse Laplace in a graphing calculator, the graph is as shown below ( with the white background and the blue line).

Why are both graphs not the same? Shouldn't they be the same?

Thank you for your replies.


Last edited:


Joined Dec 29, 2008
Are you able to adjust the horizontal scale of the scope display? It is very different from that of the graph paper.