Question

Angle between the vectors (i + j) and (j-k)
is
(A) 90°
(B) 0°
(C) 180°
(D) 60°​

Answer 1

Answer:

the answer is 90 degreee

Answer 2

Answer:

$\cos( \alpha ) = \frac{(i + j).(j - k)}{ |i + j| |j - k| } \\ \\ \cos( \alpha ) = \frac{1}{ (\sqrt{2})( \sqrt{2}) } \\ \\ \cos( \alpha ) = \frac{1}{2} \\ \\ \alpha = {60}^{0}$

OPTION (D) IS CORRECT...

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