设公比是qa5-a1=a1*q^4-a1=a1(q^4-1)=a1(q^2+1)(q^2-1)=60 (i)a4-a2=a1*q^3-a1*q1=a1q*(q^2-1)=24 (ii)(i)/(ii)=>(q^2+1)/q=60/24=5/2=>2q^2-5q+2=0=>(2q-1)(q-2)=0=>q1=1/2,q2=2因此这个数列的公比是1/2或2...