若a1=4/5,a2=4/6,a3=4/7.a20=4/24.b1=5/25,b2=6/25,b3=7/25.b20=24/25求在a1-b1,a2-b2,...a20-b20,中最小的一项是那一项,最小值是多少

Question

若a1=4/5,a2=4/6,a3=4/7.a20=4/24.b1=5/25,b2=6/25,b3=7/25.b20=24/25
求在a1-b1,a2-b2,...a20-b20,中最小的一项是那一项,最小值是多少

Answer 1

a1＋a2＋a3＝6062a2＋a3＋a4＝a1q＋a2q＋a3q＝q（a1＋a2＋a3）＝－3q＝－3＆＃47；6＝－1＆＃47；2a3＋a4＋a5＋a6＋a7＋a8＝a1q＆sup2；＋a2q＆sup2；＋a3q＆sup2；＋a4q＆sup2；＋a5q＆sup2；＋q6q＆sup2；＝q＆sup2；（a1＋a2＋a3＋a4＋a5＋a6）＝1＆＃47；4＊（6＋a4＋a5＋a6）＝1＆＃47；4＊（6＋a2q＆sup2；＋a3q＆sup2；＋a4q＆sup2；）＝1＆＃47；4＊（6－3＆＃47；4）＝21＆＃47；16