Question

The angle between the vector I+j and j+k is

Answer 1

Let angle between ( i + j ) and ( j + k )
cos∅ = ( i + j ).( j + k )/|i + j| .| j + k |
|i + j | = √(1² + 1² ) = √2
|j + k | = √(1² + 1²) = √2
cos∅ = 1/√2.√2
= 1/2
cos∅ = cos60°
∅ = 60°

Answer 2

Answer:

60°

Explanation:

According to dot product:

(i+j). (j+k) = magnitude of first vector x magnitude of second vector x cos theta

0+1+0 = root2 x root2 x cos theta

1=2cos theta

cos theta =1/2

theta=60°

Hope it helps..