Sn=1+3×2+5×2^2+7×2^3…………+(2n-1)×2^n-1
问题描述:
Sn=1+3×2+5×2^2+7×2^3…………+(2n-1)×2^n-1
求Sn
答
Sn=1×2^0+3×2+5×2^2+7×2^3…………+(2n-1)×2^n-12Sn=1×2^1+3×2^2+5×2^3+7×2^4…………+(2n-3)×2^n-1+(2n-1)×2^nSn-2Sn=2^0+2*2^1+2*2^2+2*2^3+.+2*2^n-1-(2n-1)×2^n-Sn=2^0+2*(2^1+2^2+2^3+.+2^n-1)-(2n...