# I have problem in solving ode45

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Dinesh Durai on 3 Aug 2022
Commented: Star Strider on 6 Aug 2022
clear all, close all, clc
w=2*pi;
zeta=0.25;
A=[0 1;-w^2 -zeta];
dt=0.01;
T=10;
x0=2;
[t,x] = ode45(@(t,x) A*x, 0:dt:T, x0);
plot(t, x(:,1));
i am getting error as
Error in ode45 (line 12)
[t,x] = ode45(@(t,x) A*x, 0:dt:T, x0);
i dont know what wrong i did here, if any body spoted out it will be very helful. Thank you.

Star Strider on 3 Aug 2022
The principal problem appears to be having 2 differential equations and 1 initial condition.
Try this —
w=2*pi;
zeta=0.25;
A=[0 1;-w^2 -zeta];
dt=0.01;
T=10;
x0=[0 2]; % Add Second Initial Condition
[t,x] = ode45(@(t,x) A*x, 0:dt:T, x0);
t = 1001×1
0 0.0100 0.0200 0.0300 0.0400 0.0500 0.0600 0.0700 0.0800 0.0900
x = 1001×2
0 2.0000 0.0200 1.9911 0.0398 1.9743 0.0594 1.9498 0.0788 1.9177 0.0978 1.8781 0.1163 1.8312 0.1344 1.7772 0.1518 1.7163 0.1687 1.6488
plot(t, x(:,1)); Make appropriate changes to get the desired result.
.
##### 2 CommentsShowHide 1 older comment
Star Strider on 6 Aug 2022
As always, my pleasure!

R2022a

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