Solution by fmincon?

how solve this question by function ‘fmincon’?

This is the sane problem as at "Error using cvx / prod (line 84) Disciplined convex programming error: Invalid computation: prod ({convex}) " .

Solution by fmincon is out of scope of this forum. If you seek help on another forum, you might be expected to put in at least some effort (beyond copying an image from a paper your advisor told you to implement).