Question

Question #a42a8

Answer 1

Let

`veca=hati-2hatj+hatk`
and
`vecb=3hati+hatj-2hatk`

The cross product of these two vectors (`veca and vecb`) is a vector `vecc` perpendicular to both as shown in the figure below

So
`vecc =veca xxvecb=[(hati,hatj,hatk),(hati,-2hatj,hatk),(3hati,hatj,-2hatk)]`

`=((-2)*(-2)-1*1)hati+(1*3-1*(-2))hatj+(1*1-3*(-2))hatk`

`=3hati+5hatj+7hatk`

So unit vector of `vecc=vecc/abs(vecc)`

`=(3hati+5hatj+7hatk)/sqrt(3^2+5^2+7^2)`

`=(3hati+5hatj+7hatk)/sqrt83color(red)(->"option (2)")`