验证级数∑ln(1-1/n²)是否收敛,n∈(2,∞)a‹n+1›/a‹n›=ln[1-1/(n+1)²]/[ln(1-1/n²)]=ln[(n²+2n)/(n+1)²]/[ln(n²-1)/n²]=ln[n(n+2)/(n+1)²]/ln[(n+1...