解:(20-1)×20÷2 =380÷2 =190(个) 答:在同一平面内,20条直线相交最多有190个交点。
张线:=MA(CLOSE,181);<br>牛:=EMA(CLOSE,144)>=REF(EMA(CLOSE,144),1);<br>黄昏之星:=((((((REF(CLOSE,2) / REF(OPEN,2)) > 1.03) AND (REF(OPEN,1) ><br>REF(CLOSE,2))) AND ((ABS((REF(OPEN,1) - REF(CLOSE,1))) /REF(CLOSE,1))