The sum is
13[(1/2)^0+(1/2)^1+...+(1/2)^13]
that is
13*[1-(1/2)^14]/(1-1/2)]=26[(1-(1/2)^14]
So the answer is 26[(1-(1/2)^14]
这道题难度真大,请尽快帮忙,说简单的你们自己看看楼上楼下的，答案一个都没有相同的！
The sum is
13[(1/2)^0+(1/2)^1+...+(1/2)^13]
that is
13*[1-(1/2)^14]/(1-1/2)]=26[(1-(1/2)^14]
So the answer is 26[(1-(1/2)^14]