I cannot solve this question, could you please help me?

c) At some time t, the velocity of a particle is v = (2.5 i - 1.2 j + 3.7 k) m/s and its acceleration is a = (0.3i - 0.2 j + 1.1 k) m/s2. Calculate v . a, u, u, and demostrate that v . a = v v. (Hint: remember u is not lal, check Part 1 of the homework; 3 points)