Question

What is `|| <-1, 9, -2 > - < 9 , -4, 1 > ||`?

Answer 1

`|V_r|= sqrt(278)~~16.67`

Explanation:

This effectively asking you to find the magnitude of the vector sum.
Solution Strategy:
1) Perform vector addition (subtraction)
2) Compute the magnitude of the new vector, `V_r`
Let `vec(V_1) = -i+9j-2k, and vec(V_2) = 9i-4j-k`
Then 1)
`V_r = V_1 - V_2=-i+9j-2k -(9i-4j-k)`
`V_r=(-1-9)I+(9-(-4)j +(-2-1)k`
`V_r= -10i+13j-3k`
and 2)
`|V_r| = sqrt[(-10^2+13^2+3^2) ]= sqrt[278]`