Were supposed to plot this program and I've copied it from the book correctly and it gives error. must be a typo in book Example 1.9.2 engineering vibrations 4th ed Daniel J. Inman

& se D E Dj Run Section Run Advance Run and Advance Run and Time RUN APPS EDITOR PUBLISH VIEW Insert 3 fx 1 3 Go To Comment % $ * Breakpoints Find Indent E E NAVIGATE EDIT BREAKPOINTS donal Editor - C:\Users\donal\sdof.m vib. mxsdof. mx + 1- t=0:0.001:20; 2 function xdot = sdof (t, x); 3 - xdot = zeros (2,1); xdot = x(2); xdot = -(2/3)*x (1)-(1/3)*x(2); Command Window >> t0 = 0;tf = 20; x0 = [0 0.25); [t, n] = ode 45 ('sdof'[to tf], 0); [t, n] = ode45('sdof' [to tf], 0); Error: Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters. fx >>