# How to calculate vectors

1. Jan 12, 2010

### Bingo1915

How can I calculate the following?
Given A=$$\hat{x}$$(x+2y)-$$\hat{y}$$(y+3z)+$$\hat{z}$$(3x-y)
Determine a unit vector parallel to A at point P(1,-1,2).

2. Jan 12, 2010

### Born2bwire

It's straight forward substitution. Find the vector A at the given point and then calculate the unit vector by scaling A by the inverse of its length (thus making the new vector's length one).

3. Jan 13, 2010

### RTW69

I agree. By substitution A=-1i-5j+4z, The magnitude of A = Sqrt((-1)2+(-5)2+(4)2). Divide the magnitude into A to get the unit vector.