Inverse system in Simulink I have the following inverse system

$$G(s)= s^2 + 2s + 3$$

How do I implement it in Simulink? Note that the transfer function is only accepted if and only if the order of the numerator is less than the order of denominator.
You will have to implement the transfer function in pieces, rather than as a single LTI block.  See http://www.mathworks.com/support/solutions/en/data/1-VPJDU