Find the resultant of vectors `veca=hati-hatj+2hatk and vecb=hati+2hatj-4hatk`. Find the unit vector in the direction of the resultant vector.

Explanation

Let the resultant vector of `veca and vecb` is `veca+vecb=2hati+hatj-2hatk=vecc`
Now unit vector in the direction of `vecc` is `hatc=(2hati+hatj-2hatk)/(sqrt((2)^(2)+(1)^(2)+(-2)^(2))=(1)/(3)(2hati+hatj-2hatk)`