1. The problem statement, all variables and given/known data Verification of the product U . del (R) = U Vectors are written in bold 2. Relevant equations R = ix + jy + kz 3. The attempt at a solution I cannot understand what is going on. If del R is the gradient vector of R, then the problem will be scalar product, whose answer is Ux + Uy + Uz, not a vector as it is written on the book. And if del R is the scalar product of del and R, then the answer is going to be a vector, but it will be 3U not only U.