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## Homework Statement

show that [itex]\nabla \times (f F)= f \nabla \times F+ (\nabla f) \times F[/itex]

## The Attempt at a Solution

How will I represent the scalar function? Do I write [itex]f=\psi(x,y,z)[/itex] or

[itex]f=A_x+A_y+A_z[/itex]

I chose [itex]F=a_x \vec i +a_y \vec j +a_z \vec k[/itex]

Using [itex]f=\psi(x,y,z)[/itex] I work out the LHS of question as

[itex](\psi a_z)_y-(\psi a_y)_z-(\psi a_z)_x+(\psi a_x)_z+(\psi a_y)_x-(\psi a_x)_y[/itex].............How to go further?

Thanks