等比数列中,若a1a2a3.A99=2^99则a2a5a8...a98=
问题描述:
等比数列中,若a1a2a3.A99=2^99则a2a5a8...a98=
答
a1a2a3.A99=a1^99*q^*99*(0+98)/2=2^99
a2a5a8...a98=a1^48*q^*48*(2+97)/2
有问题吧a2a5a8...a98=?a2a4a8...a98=