用数学归纳法证明“(n+1)(n+2).(n+n)=1*3*...*(2n-1)*2^n”时“从k到k+1”左边需要增乘的代数式是

问题描述:

用数学归纳法证明“(n+1)(n+2).(n+n)=1*3*...*(2n-1)*2^n”时“从k到k+1”左边需要增乘的代数式是

n=1.2=2.成立.设n=k时成立:(k+1)(k+2).(k+k)=1*3*...*(2k-1)*2^k.看n=k+1:左边=[(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)=[1*3*...*(2k-1)*2^k]...