HP PPL How to pick a CAS expression off the stack?

[Chris Pem10]

Suppose I have the following three CAS results on the right hand side of the "stack":

SIN(x)
COS(x)
TAN(x)

From within a program, I'd like to store expression SIN(x) in a variable eq1, skip the COS(x) expression, and store expression TAN(x) in variable eq2. This was simple in previous RPN calcs, but I'm not sure how to do this in the Prime?

Code:


EXPORT READ_FROM_STACK()
  LOCAL eq1, eq2;
  code to pick expressions off the stack....
END;

I was looking for something in the spirit of:

Code:


sto(Ans(1),eq1);

but I haven't had any success yet.