If ϕ=ϕ(x,y,z)=4x3y sin z,\phi=\phi(x,y,z)=4x^{3}y\,\mathrm{sin}\,z,ϕ=ϕ(x,y,z)=4x3ysinz,, find ∇Φ.
so that by partial differentiation we obtain
Therefore