Non linear optimization

this is a convex problem with non-linear constraint as well as nonlinear objective function \rho\geq \rho_{min} ,i have tried many times it in fmincon matlab under various headings but i am not getting results. Now, i have to go into cvx. I will be obliged if anyone could help me to solve it. Thanks a ton in advance. Please give me a routine to solve it.plzzzzzzzz
\begin{equation}
\underset{p_{s},p_{r}} {\text {minimize}}
\quad C = w_1.(\frac{p_{s}+p_{r}}{p_{max}}) + w_2.{\frac{\rho_{min}}{\rho}}
\end{equation}
\begin{equation}
\begin{aligned}
\text{subject to}
& \rho\geq \rho_{min},\quad \text{non linear constraint} \newline
& p_{s}+p_{r}\leq p_{max},\quad \text{linear constraint}\newline
& p_{s}\geq 0, p_{r}\geq 0.
\end{aligned}
\end{equation}

where , \begin{equation}
\begin{aligned}
& \rho = \frac{\phi_{1}\phi_{2}p_{s}p_{r}}{\phi_{1}p_{s} + \phi_{2}p_{r} + 1}\newline &w_{1}+w_{2}=1,& w_{1}=.5,w_{2}=.5 \newline &\phi_{1}=6.7;
\phi_{2}=7.5 \quad(\text{i have to repeat it for 10000 different values of \phi_1 \& \phi_2)} \newline
& \rho_{min}=10;\quad & \quad p_{max}=100.
\end{aligned}
\end{equation}

I’m pretty sure this problem is not convex and thus can’t be solved with CVX. Here’s my reasoning: The constraint \rho\ge\rho_{\min} is

\phi_1\phi_2p^T\pmatrix{0&-1/2\\-1/2&0}p\ge\rho_{\min}(\phi_1p_s+\phi_2p_r+1)

where p=(p_s,p_r)^T. The matrix on the left hand side has eigenvalues of mixed sign, meaning this quadratic is not concave as would be required to make the problem convex.

I am going to refer you to the answer I gave to your previous question.) This forum is not intended to help you formulate optimization problems; it is intended to help you use CVX properly. In order to use CVX properly, not only must you prove your problem is convex, but you must use CVX’s built in functions and the disciplined convex programming ruleset to do so.

ok i m sry about posting this question here…