 HP Prime: Slopefield (Differential Equations) - Printable Version +- HP Forums (https://www.hpmuseum.org/forum) +-- Forum: HP Software Libraries (/forum-10.html) +--- Forum: HP Prime Software Library (/forum-15.html) +--- Thread: HP Prime: Slopefield (Differential Equations) (/thread-5274.html) HP Prime: Slopefield (Differential Equations) - Eddie W. Shore - 12-05-2015 05:11 AM HP Prime: Slopefield (Differential Equations) Adopted from Alan Ziv’s Casio program – ported to the HP Prime http://edspi31415.blogspot.com/2015/12/hp-prime-slopefield-differential.html Program: Code: ``` EXPORT SLOPEFIELD(dxy) BEGIN // dxy: dx/dy = f′(x,y) // Adopted from Alan Ziv - // Casio // dxy is in quotes LOCAL X,Y,C,D,J,K,G,H; LOCAL F,xa,xb,ya,yb,E; // Use the Function App RECT(); C:=(Ymax-Ymin)/220; D:=(Xmax-Xmin)/320; FOR J FROM 0 TO 50 DO E:=Xmin+(8*J+3)*D; FOR K FROM 0 TO 27 DO F:=Ymin+(8*K+3)*C; X:=E; Y:=F; G:=EXPR(dxy); H:=2*D; IF ABS(G)>C/D THEN H:=2*C/ABS(G); END; IF 2*H>D THEN xa:=E-H; ya:=G*(xa-E)+F; xb:=E+H; yb:=G*(xb-E)+F; LINE(xa,ya,xb,yb); ELSE LINE(E,F+2*C,E,F-2*C); END; END; END; // Draw Axis LINE(Xmin,0,Xmax,0,#C0C0C0h); LINE(0,Ymin,0,Ymax,#C0C0C0h); WAIT(0); END;```