来自耿福昌的问题
[3n(n+1)+n(n+1)(2n+1)]/6+n(n+2)化简
[3n(n+1)+n(n+1)(2n+1)]/6+n(n+2)化简
1回答
2020-04-11 12:26
[3n(n+1)+n(n+1)(2n+1)]/6+n(n+2)化简
[3n(n+1)+n(n+1)(2n+1)]/6+n(n+2)化简
原式=(3n²+3n+2n²-3n²+n+6n²+12n)/6
=(2n²+6n²+16n)/6
=(n²+3n+8)/3