Question

What is the angle between `<7,-2,8>` and `< 7,3,-8>`?

Answer 1

Angle `theta=100.12^0`

Explanation:

Let `vecu =<7,-2, 8> and vecv =<7,3,-8> ; theta` be the angle between them ; then we know `cos theta= (vecu*vecv)/(||vecu||*||vecv||)=((7.7)+(-2*3)+(8*-8))/(sqrt(7^2+(-2)^2+8^2)* (sqrt(7^2+3^2+(-8)^2))` `= (-21)/(sqrt117*sqrt122)=-0.1757:. theta=cos^-1(0.1757)=100.12^0`[Ans]