## Thomas' Calculus 13th Edition

$$3\pi$$
We know that $$div F=\dfrac{\partial P}{\partial x}i+\dfrac{\partial Q}{\partial y}j$$ From the given equation, we have $$Flux =\iiint_{o} 3x \space dz \space dy \space dx\\=\int_{0}^{\pi/2}\int_{0}^{\pi/2}\int_{0}^{2} (3 \rho \sin \phi \space \cos \theta) \times (\rho^2 \sin \phi) \space d\rho \space \space d\phi \space d\theta\\= \int_{0}^{\pi/2}(3\pi \cos \theta) d\theta \\= 3\pi$$