How can I express this concave function in CVX

10

thank you, I wrote this and I get an error
Error using .* (line 173)
Disciplined convex programming error:
Cannot perform the operation: {positive constant} ./ {real affine}
Error in ./ (line 19)
z = times( x, y, ‘./’ );

Error in harmmean (line 28)
m = 1 ./ mean(1./x, varargin{:});

Error in Q2 (line 21)
u <= harmmean([g.*x,h.*y],2)

N = 10;
g = ones(N,1);
h = ones(N,1);
cvx_begin
    variable x(N,1) nonnegative
    variable y(N,1) nonnegative
    expression u(N,1)
    maximise sum_log(1+u)
    subject to
    u <= harmmean([g.*x,h.*y],2)
    sum(x + y) == 5
cvx_end