Slopefield program - graphs slopefields for certain differential equations on TI-85 ----begin documentation---- This program will graph a slopefield for any differential equation in the form dy/dx = g(x,y), i.e. d.e.'s in which solving for dy/dx yields an expression involving only x and y. Example: dy/dx = y/x **Instructions for use:** 1) Store expression equal to dy/dx in equation y1. Use lower-case x and y for variables. 2) Use the [GRAPH][RANGE] menu to set desired window. 3) Run program. **Program notes:** Draws an array of line segments of the appropriate slope. Each "box" in this grid is 2H wide and 2K tall (the program sets H and K automatically). 18 columns and 9 rows of segments are drawn, with each segment 6 pixels wide or 6 pixels tall (2*H1+1 or 2*K1+1, respectively). For each segment, the program first decides if the limit of the line segment should be determined by the horizontal or vertical edges of the grid "box". Written by Prof. Mark Janeba Dept. of Mathematics Willamette University, Salem, OR 97301 internet: mjaneba< at >willamette.edu www: http://www.willamette.edu/~mjaneba/ ----end documentation---- ----begin ASCII---- \START\ \COMMENT=Program file dated 01/01/90, 02:16 \NAME=SlpFe \FILE=slpfe.85P FnOff ClDrw DispG 3.5\Delta-x\\->\H 5H/7\->\H1 3.5\Delta-y\\->\K 5K/7\->\K1 K/H\->\MT For(x,xMin+H,xMax,2H) For(z,yMin+K,yMax,2K) z\->\y y1\->\T If abs T\<=\MT:Then T*H1\->\R Line(x-H1,z-R,x+H1,z+R) Else K1/T\->\R Line(x-R,z-K1,x+R,z+K1) End End End \STOP\ ----end ASCII---- ----begin UUE---- begin 644 slpfe.85p M*BI423@U*BH:#`!0