求1-1/2+1/4-1/8+…+(-1)的n次方×[1/(2的n次方)]的极限,n→∞,

问题描述:

求1-1/2+1/4-1/8+…+(-1)的n次方×[1/(2的n次方)]的极限,n→∞,

lim(n→∞)[1-(-1/2)^n]/[1-(-1/2)]=1/(1+1/2)=2/3