問題詳情:
用數學歸納法*:(n+1)+(n+2)+…+(n+n)= (n∈N*)的第二步中,當n=k+1時等式左邊與n=k時等式左邊的差等於________.
【回答】
3k+2
[解析] [(k+1)+1]+[(k+1)+2]+…+[(k+1)+(k+1)]-[(k+1)+(k+2)+…+(k+k)]
=[(k+1)+k]+[(k+1)+(k+1)]-(k+1)
=3k+2.
知識點:推理與*
題型:填空題