It looks to me that you're nearly there! I found a couple of small mistakes that seems to be holding you back.

Changes to your code:

- Replace ode45 with you defined euler function
- Read the documentation of your euler function. Unlike ode45 which is a variable step numerical solver, Euler's method is a fixed step solver. As such, you need to specify the number of steps you want to take, N, as the final fuction input. I would imagine 250+ steps would be sufficient for this problem.

Changes to your euler function:

- The two outputs of the function [te,Ye] are never defined in the code. From what I can tell, the outputs should be changes to [t,y].

Hope this helps to rectify the problem!