\frac{\text{dP}(H)}{\text{dH}}=0\Leftrightarrow \text{  }\sqrt{3V} \left(-H^{-2}\left(H^3 \pi +3 V\right)^{\frac{1}{2}}+H^{-1}\frac{1}{2}\left(H^3 \pi +3 V\right)^{-\frac{1}{2}}3H^2\pi \right)=3 \frac{V}{H^2}