问题
填空题
等比数列{an}中an>0,且a5•a6=9,则log3a2+log3a9=______;
答案
因为a5•a6=a1q4•a1q5=a12q9,而a2•a9=a1q•a1q8=a12q9,
所以a5•a6=a2•a9=9,
则log3a2+log3a9=
=log a2a93
=log a5a63
=2.log 323
故答案为:2
等比数列{an}中an>0,且a5•a6=9,则log3a2+log3a9=______;
因为a5•a6=a1q4•a1q5=a12q9,而a2•a9=a1q•a1q8=a12q9,
所以a5•a6=a2•a9=9,
则log3a2+log3a9=
=log a2a93
=log a5a63
=2.log 323
故答案为:2