Question

Find a unit vector in the direction from point P
(1,-1,2) to point Q (-1,1,1)

Answer 1

its much simpler than it seems, use below :

\(\large \overrightarrow{PQ} = \overrightarrow{OQ} - \overrightarrow{OP}\)

Answer 2

\(\large \overrightarrow{PQ} = \langle -1,1,1\rangle - \langle 1,-1,2 \rangle \)
\(\large ~~~~~~= \langle -2,2,-1\rangle \)

Answer 3

upon the product of their magnitudes
"3"

Answer 4

right?
But how to know in which order to subtract

Answer 5

"corresponding components"

Answer 6

nope not that

Answer 7

elaborate

Answer 8

head of the arrow - tail

Answer 9

why?^^

Answer 10

the implicit assumption was that there is origin sitting somewhere

Answer 11

OP + PQ = OQ
PQ = OQ - OP