**TI92P*mainDirectional Derivative v0.1 RddZ3esRReturn f/s=esEndFori+1i If (t|d and a=i)<0:Return f/s=es|d and a=i and (d|a=i)For i,1,6(es,,2)tarbint(1)a:solve((es,)=0,)d(es,)d:solve(d=0,)d:Return f/s=es and d:VAR- ;,esespltdd(ok,ERROR,ok-dd(e,|[v],{x=,})-R Return esplDplEes esRplDplEespl𱱇;EXPR- VAR- NUM- ㇃pll9kesResRd:eses eslesest;pllples 2esespltpllples=-pl𱱇;MAT- ;Define arbint(n)=expr("@n"&string(expr(mid(string(explist(solve(0=sin(x*),x),x)[1]),3))+n))pllarbintes }dd(e,|[v],{x=,})e1 Directional Derivative v0.1 e: Expression : Angle or v: Vector matrix {x: Variables (and points) e1: Solution expression or value Ex: dd(x+y,/4,{x=1,y=1}) Ex: dd(x+y,[1,1],{x=1,y=1}) Ex: dd(x+y,[1,1],{x,y}) Frank P. Westlake -pl_