1. The problem statement, all variables and given/known data Express the quantity ∂2/∂x2+∂2/∂y2 in polar coordinates. 2. Relevant equations x=ρcosφ y=ρsinφ ρ=sqrt(x2+y2) 3. The attempt at a solution This is my first post, so I apologize for any weird looking equations, etc. I know that this is not a difficult problem, but I just cannot figure out exactly how to set it up. I don't know what function to differentiate for x and y... Any guidance would be appreciated. Thank you!