What is the angle between <-3,2,0> and < 5,0,2 >?

1 Answer

theta=cos^-1(-5/14)~~111

Explanation:

We will use the definition of the dot product:
vec(v_1)*vec(v_2) = |vec(v_1)||vec(v_1)|costheta
costheta=(vec(v_1)*vec(v_2))/(|vec(v_1)||vec(v_1)|)
Now substituting vec(v_1) =<-3,2,0> and vec(v_2)=<5,0,2>

costheta=(-15+0+0)/ (((-3)^2+2^2)*(5^2+2^2))= -5/14

theta=cos^-1(-5/14)~~111^o