can any body tell me how to do state space modelling and get their responses of states

if I have three differential equations and inputs and out puts variables, how to do this means states are there, A matrix is there, output vector is there, but how to do coding and plots the states

[Walter Roberson]

Please read the guide to tags and retag this question. See http://www.mathworks.co.uk/matlabcentral/answers/43073-a-guide-to-tags