# ApCoCoA-1:DA.InitialOfDer

From ApCoCoAWiki

## DA.InitialOfDer

Computes the initial wrt. a given derivative.

### Syntax

DA.InitialOfDer(F:POLY, X:INDET):POLY

### Description

DA.InitialOfDer returns the polynomial leading coefficient of polynomial F regarded as polynomial in the derivative X.

@param

*F*A differential polynomial.@param

*X*A indeterminate.@return Initial of F wrt. X.

#### Example

Use QQ[x[1..2,0..20]]; Use QQ[x[1..2,0..20]], Ord(DA.DiffTO(<quotes>Lex</quotes>)); F:=x[1,2]^3x[2,2]^2 + x[1,1]^3x[2,2]^2 + 1/4x[1,2]; DA.InitialOfDer(F, x[1,2]); ------------------------------- x[2,2]^2 -------------------------------