wusagi22
幼苗
共回答了20个问题采纳率:90% 举报
记极限符号内的表达式为a,
则a=(1-1/2²)x(1-1/3²)x(1-1/4²)...(1-1/n²)
=[(2^2-1)/2^2]x[(3^2-1)/3^2]x[(4^2-1)/4^]...[(n^2-1)/n^2]
=(1x3/2^2)x(2x4/3^2)x(3x5/4^2)...[(n-1)x(n+1)/n^2]
=[1x(n+1)]/(2n)
=(n+1)/(2n)
所以n趋近于无穷大时,原式=lim a=lim (n+1)/(2n)=1/2
1年前
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