Error using vertcat and how to solve it?

Hello everyone, I am getting Error using vertcat, Dimensions of arrays being concatenated are not consistent, error for the following code. Can anyone please point me out my error and how to fix it.

clc
clear all

f = @(t,x) [-x(4)-(0.424)+(1.6977)*exp(-1.35*10^20*(x(1)^2));
            x(4)-(0.663)+(2.6540)*exp(-1.35*10^20*(x(2)^2));
           -(2.994*10^5)*x(4);
           (7.124*10^17*(x(1)^2)-7.124*10^17*(x(2)^2)+x(3)+60*(cos(t))) -2.55*10^7*x(4)];
       
[t,xa] = ode45(f,[0, 80],[0,0,-62,0]);

Answer 1

[Stephen23]

f = @(t,x) [-x(4)-(0.424)+(1.6977)*exp(-1.35*10^20*(x(1)^2));
    x(4)-(0.663)+(2.6540)*exp(-1.35*10^20*(x(2)^2));
    -(2.994*10^5)*x(4);
    (7.124*10^17*(x(1)^2)-7.124*10^17*(x(2)^2)+x(3)+60*(cos(t)))-2.55*10^7*x(4)];
%                                                              ^^ removed space character

A space character is a delimiter that separates elements horizontally, equivalent to a comma. Because of that space character you were trying to concatenate rows together which had [1,1,1,2] columns. Clearly that doesn't work.