Question

Find the angle between a=3i+2j+k b=5i-2j-3k

Answer 1

Answer:

cos inverse 2/57

Explanation:

we know , A.B =mod of A . mod of B . cosΘ

therefore A.B = 3i.5i + 2j.(-2j) + k.(-3k) = 8

mod of A = (3i)^2 + (2j)^2 + (k)^2 = 6

mod of B = (5i)^2 + (-2j)^2 + (-3k)^2 = 38

therefore , 8 = 6.38.cosΘ

              or. 8 = 228.cosΘ

              or, cosΘ = 2/57

              or, Θ cos inverse 2/57

 hope it helps