Hello :
v . w = <span>| | v | | × </span><span>| | w | | cos(</span><span>θ) ....(1)
v(2,0,1) w(0,1,-3)
</span>v . w = (2)(0)+(0)(1)+(1)(-3) = - 3
| | v | | = √((2)²+(0)²+(1)²) = <span>√5
</span>| | w | = √((0)²+(1)²+(-3)²) = √10
by (1) :
cos(θ) = (v . w ) / | | v | | × | | w | |
cos(θ) = = - 3/√50
θ =..... calculate by 2ind function ( calculator)
The answer is D
Have you ever heard of rise over run rise/run
Y/x. Well in this case the run is One with a rise of four
