Determine the unit vector in the direction of P = 2i-4j+4k.

the corresponding unit vector would be

P = P / |P| = (2i - 4j + 4k) / (4 + 16 + 16)^1/2

or

P =  (2i - 4j + 4k) / 6 = (1/3)i - (2/3)j + (2/3)k