100 OPEN #1:NAME "data4.txt" 110 LET left=100 120 LET right=200 130 LET bottom=0 140 LET top=100 150 SET WINDOW left,right,bottom,top 160 DRAW grid WITH SCALE(10,10) 170 DO 180 INPUT #1,IF MISSING THEN EXIT DO: x,y 190 PLOT POINTS:x,y 200 LOOP 210 GET POINT: x1,y1 220 SET LINE COLOR 4 230 GET POINT:x2,y2 240 LET a=(y2-y1)/(x2-x1) 250 LET b=y1-a*x1 260 PRINT "a=";a,"b=";b 270 PLOT LINES:left,a*left+b;right,a*right+b 280 SET #1:POINTER BEGIN 290 LET t=0 300 SET LINE COLOR 2 310 DO 320 INPUT #1,IF MISSING THEN EXIT DO: x,y 330 LET y0=a*x+b 340 LET t=t+(y-y0)^2 350 PLOT LINES:x,y;x,y0 360 LOOP 370 PRINT t 380 CLOSE #1 390 END