unit vectors

[hayood]

Find two unit vectors that are orthogonal to (-3,4).
- so i was thinking maybe have the vector (-4,-3) and then multiply the first vector with this one and get a 0, meaning it is orthagonal. The answer is (4/5,3/5) and (- 4/5, -3/5) but i dont understand the way it is done.

 

[Aladdin]

I can get you many, not only two .Think of it :

XX' + YY' = 0

(-3)(1/3) + (4)(-1/4) = -1 + 1= 0 . . .

So V(1/3,-1/4) is a vector perp. to U(-3,4).

 

[hayood]

but how did they get (4/5 ,3/5) and (-4/5, -3/5)? i don't know how to start solving it.