a2a4+2a3a5+a4a6=a1^2q^4+2a1^2q^6+a1^2q^8=a1^2q^4(1+2q^2+q^4)=a1^2q^4(q^2+1)^2=[a1q^2(q^2+1)]^2=25an>0,a1>0 q>0a1q^2(q^2+1)=5a3+a5=a1q^2+a1q^4=a1q^2(1+q^2)=5在等比数列an中,若an>0且a2a4+2a3a5+a4a6=25,则...