第四个是√4+1/6=5√1/6
第n个等式为√n+1/(n+2)=(n+1)√1/(n+2)
证明:√n+1/(n+2)=√(n^2+2n)/(n+2)+1/(n+2)
=√(n^2+2n+1)/(n+2)
=√(n+1)^2/(n+2)
=(n+1)√1/(n+2)
第四个是√4+1/6=5√1/6
第n个等式为√n+1/(n+2)=(n+1)√1/(n+2)
证明:√n+1/(n+2)=√(n^2+2n)/(n+2)+1/(n+2)
=√(n^2+2n+1)/(n+2)
=√(n+1)^2/(n+2)
=(n+1)√1/(n+2)