if n is a positive integer and 2^n + 2^n+1=k,what is 2^n+2 in terms of

题目

if n is a positive integer and 2^n + 2^n+1=k,what is 2^n+2 in terms of

答案

翻译：如果n大于0（即n属于正区间）,而且2^n + 2^n+1=k,那么,用k来表示2^n+2为多少?
由2^n + 2^n+1=k
推出3*2^n =k,
那么2^n=k/3,
于是2*2*2^n=2*2*k/3,即 2^n+2=4k/3