【類9】已知<a> 為等差數列、A =a+a+...+am;
<b >為等比數列、B = b +62 + ...+b;試問下列敘述何者正確?
n
n
(1) {40,420,43, 440} 亦為等差數列
(2)
(3)
{Bro, B20, B30,B40} 亦為等比數列
10,
60
(4) {B30-B20,B40-B30, B50-B40,Bo-B50}亦為等比數列
(5) {a+a+a,a2 +a +a,a, +a+q} 亦為等差數列
{40,420-40,430-A20 A40- 430} 亦為等差數列
10: