In Taylor's theorem let Y be the state vector  , and use it to
estimate to 2nd order, the value of
, and use it to
estimate to 2nd order, the value of  given
 given  ,
,  and
 and
 .
Call the value we obtain in this way
.
Call the value we obtain in this way  to indicate that it is the result of the
predictor step.
 to indicate that it is the result of the
predictor step. 

Where for some  in
 in  ...
... 

As the differential equations only give us the value of the first derivative in terms
of time and value of the state variable, we need an estimate of the second derivative. Now
use Taylor's theorem again to estimate the value of  using
 using  and
 and
 .
Note that this time we use
.
Note that this time we use  in Taylor's theorem.
 in Taylor's theorem. 

Where for some  in
 in  ...
... 

Which we can solve for  ...
... 

Now define  .
. 
Inserting this into the predictor...
Predictor

Where... 

Which is... 
