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Topic: How to get second derivatives using ode45
Replies: 4   Last Post: Apr 30, 2013 11:15 AM

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stanley ontario

Posts: 3
Registered: 4/30/13
How to get second derivatives using ode45
Posted: Apr 30, 2013 9:49 AM
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I am stuck in solving a problem with ode45. I would like to get the second derivatives in order to plot the acceleration and to calculate some other values.

However I only get the velocity and position.

It looks like this:

options= odeset('RelTol',1e-3,'AbsTol',1e-6);
[t_vec,Y]=ode45(@(t,y) vib_equ(t,y,c_s_f,c_s_r,v_val,F_d_val,m_c,I_g_c,l,l_f,l_r,u_f,u_f_dot,v,L,i_d),[0 t_max], zeros(1,4), options);

z_cf= Y(:,1);
z_cf_dot= Y(:,2);
z_cr= Y(:,3);
z_cr_dot= Y(:,2);

I would like to use the function vib_equ to get both z_cf_ddot and z_cr_ddot but I cannot figure it out, maybe there is another way, much easier but I really don't know.

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