I am getting the below error when i try to code the VDP equation and then solve it with ode45. I am pretty new to Matlab, so it might be something obvious that just escapes my eyes. I tried searching for answers, but without success.
Equation is (δ^2 x)/(δt^2 )-μ*(1-x^2 ) *δx/δt+x=0 where time span is 0 to 25, m=1 and x(0)=0 and x'(0)=2.5
Any help/guideline will be appreciated.