1 votes 1 votes Let $x=(x_1, x_2, \dots x_n) \in \{0,1\}^n$ By $H(x)$ we mean the number of 1's in $(x_1, x_2, \dots x_n)$. Prove that $H(x) = \frac{1}{2} (n-\Sigma^n_{i=1} (-1)^{x_i})$. Quantitative Aptitude descriptive isi2014 quantitative-aptitude proof + – go_editor asked May 30, 2016 go_editor 356 views answer comment Share Follow See 1 comment See all 1 1 comment reply Utk commented May 30, 2016 reply Follow Share What do we mean by 'x'? Is it the set of n, n-bit binary numbers? How do we build set x? How do we consider the elements in set x? 0 votes 0 votes Please log in or register to add a comment.