已知数列{An}满足A1=log13(8),An+1=An*logn+1(n+2),则A12等于
问题描述:
已知数列{An}满足A1=log13(8),An+1=An*logn+1(n+2),则A12等于
答
a12=a11log12,13=a10log11,12log12,13=……=a1log2,3log3,4log4,5……log12,13=a1(lg3/lg2)(lg4/lg3)(lg5/lg4)……(lg13/lg12)=a1*lg13/lg2=lg8/lg13 *lg13/lg2=lg8/lg2=log2,8=3