計(jì)數(shù)之歸納法練習(xí)五
1.在應(yīng)用數(shù)學(xué)歸納法證明凸n邊形的對(duì)角線為n(n-3)條時(shí),第一步驗(yàn)證n等于 ( )
A.1. B.2; C.3; D.0;
2.已知Sn=則S1=________S2=_______S3=______
S4=________猜想Sn=__________.
3.用數(shù)學(xué)歸納法證明:1+2+3+…+n2=則n=k+1時(shí)左端在n=k時(shí)的左端加上_________
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