DEF f(x) = x/2

SET WINDOW -1.2,3.2,-1.2,3.2
DRAW grid
PLOT LINES: -1.2,0;3.2,0
PLOT LINES: 0,-1.2;0,3.2
SET LINE width 3
FOR x=0 TO 2 STEP 0.01
   PLOT LINES: x,f(x);
NEXT x
PLOT LINES
PLOT LINES: 2,0;2,1
PRINT

SET LINE COLOR 3
FOR x=-1 TO 1 STEP 0.01
   PLOT LINES: x,f(1-x);
NEXT x
PLOT LINES
PLOT LINES: -1,0;-1,1

SET LINE COLOR 4
FOR x=0 TO 2 STEP 0.01
   PLOT LINES: x,f(2-x);
NEXT x
PLOT LINES
PLOT LINES: 0,0;0,1

SET LINE COLOR 7
FOR x=1 TO 3 STEP 0.01
   PLOT LINES: x,f(3-x);
NEXT x
PLOT LINES
PLOT LINES: 1,0;1,1

LET Q1=0
FOR x=0 TO 2 STEP 0.00001
   LET Q1 = Q1 + f(x)*0.00001
NEXT x
PRINT "　0≦x≦2 の f(x)=x/2 の定積分の近似値：";
PRINT Q1

LET Q2=0
FOR x=0 TO 1 STEP 0.00001
   LET Q2 = Q2 + (f(x)*f(1-x))*0.00001
NEXT x
PRINT "　0≦x≦1 の f(x)とf(1-x)の内積の近似値：";
PRINT Q2*100;"×10^(-2)"

LET Q3=0
FOR x=0 TO 2 STEP 0.00001
   LET Q3 = Q3 + (f(x)*f(2-x))*0.00001
NEXT x
PRINT "　0≦x≦2 の f(x)とf(2-x)の内積の近似値：";
PRINT Q3*100;"×10^(-2)"

LET Q4=0
FOR x=1 TO 2 STEP 0.00001
   LET Q4 = Q4 + (f(x)*f(3-x))*0.00001
NEXT x
PRINT "　1≦x≦2 の f(x)とf(3-x)の内積の近似値：";
PRINT Q4*100;"×10^(-2)"
PRINT
PRINT "　ちなみに、黒図と緑図の重なりの面積 ＝ 1/8 ＝ 0.125"
PRINT "　ちなみに、黒図と赤図の重なりの面積 ＝ 1/2 ＝ 0.5"
PRINT "　ちなみに、黒図と桃図の重なりの面積 ＝ 5/8 ＝ 0.625"

END