Help System (web edition)

DER <function of variable x>,<variable x> 
forms the analytical derivative of the function with respect to
<variable x> and writes the result on the next two lines in the edit
field. For example,
   10 *
   11 *DER log(log(1+sqr(Z))) Z
   12 * Derivative of log(log(1+sqr(Z))) with respect to Z is
   13 *    1/(2*SQR(Z))/(1+sqr(Z))/log(1+sqr(Z))
   14 *
   15 *DER SIN(G(t)/t) t
   16 * Derivative of SIN(G(t)/t) with respect to t is
   17 *    COS(G(t)/t)*(t*G'(t)-G(t))/t^2
   18 *
Survo employs itself analytical derivatives in the ESTIMATE operation
for linear and nonlinear regression models and for general Maximum
likelihood estimation problems.
  M = More information on mathematical operations