100 '   programma 10   OPPERVLAK ONDER EEN KROMME
110 CLEAR ,19202 : SCREEN 105,,3,3
120 DEF FNX(X)=INT(1.55*(50+X)+.5)
130 CLS: KEY OFF
140 V=160: H=.5: K=100: PI=4*ATN(1): C=2*PI/320
150 FOR J=0 TO 320
160     X=C*J-PI : GOSUB 1000
170     Y=INT(V-K*Y+H)
180     LINE (FNX(J),V)  (FNX(J),Y),1
190 NEXT J
200 LINE (FNX(0),0)  (FNX(320),320),1,B
210 A$=INKEY$: IF A$="" THEN 210
220 CLS: KEY ON: END
230 '
1000 Y=COS(X)-COS(3*X)/3+COS(5*X)/5-COS(7*X)/7
1010 RETURN
