初三数学题1请写详细些，谢谢！
请写详细些，谢谢！
①填1+1/6, ②1+1/n^+1/(n+1)^=1+[(n+1)^+n^]/[n(n+1)]^ =1+(2n^+2n+1)/[n(n+1)]^ =1+2/[n(n+1)]+1/[n(n+1)]^ ={1+1/[n(n+1)]}^. ②、③填1+1/[n(n+1)].