10 CLS
20 PRINT "INTEGRATION: TRAPEZOIDAL RULE" 
30 PRINT 
40 REM       DEFINE YOUR FUNCTION IN LINE 210
50 PRINT "ENTER 0,0 TO END PROGRAM)" 
60 PRINT "INTEGRATION LIMITS (LOWER, UPPER)"; 
70 INPUT A,B 
80 IF A=B THEN 230  
90 PRINT "NUMBER OF INTERVALS"; 
100 INPUT N 
110 I=0 
120 D=(B-A)/N
130 FOR J=A TO B+D STEP D 
140 X=J : GOSUB 210  : I=I+X
150 NEXT J 
160 X=A : GOSUB 210  : A=X : X=B : GOSUB 210  
170 I=(I-(A+X)/2)*D
180 PRINT "INTEGRAL =";I
190 PRINT 
200 GOTO 60   
210 REM DEFINE  FUNCTION HERE (X="FUNCTON")
220 RETURN
230 END