Vectors `vec(A) and vec(B)` can be expressed as `vec(A)=10hati-12hatj+5hatk and vec(B)=7hati+8hatj-12hatk`
where `hati,hatj,hatk` are unit vectors along x,y,z axes respectively. Find the resultant of two vectors and its magnitude.

Explanation

The resultant vector
`vec(C)=vec(A)+vec(B)=(10+7)hati+(-12+8)hatj+(5-12)hatk or, vec(C)=17hati-4hatj-7hatk`
Magnitude of the resultant,
`c=sqrt(17^2+(-4)^2+(-7)^2)=sqrt(354)=18.81`.