Hi Cassandra,
I understand that you are facing difficulty in working with the “quiver” function used for plotting in MATLAB.
Regarding the specific error you pointed out i.e. “input arguments must be numeric or objects which can be converted to double", this is caused by the symbolic variables:
sysm t y
This is incompatible with the “quiver” function. It only accepts numeric values or similar objects as mentioned in the error message as well. Refer to the below documentation to know more about the “quiver” function:
Your second question can be catered by changing the initial conditions (“t0” and “y0”) in the definition of your function “f(t,y)”, in order to visualise the change from different starting points. Furthering this purpose, you can also consider different methods of plotting which are more suited for solution trajectories. Refer to the below documentation to know more about the plotting method in MATLAB:
Hope it helps,
Regards,
Ayush Misra