Given A=i+j+k and B=-i-j-k, then (A-B) will make what angle with A
Kindly refer to the following link,
https://www.meritnation.com/ask-answer/question/if-vectors-are-a-i-j-k-and-vector-b-i-j-k-then-find-the/physics/7512621
https://www.meritnation.com/ask-answer/question/if-vectors-are-a-i-j-k-and-vector-b-i-j-k-then-find-the/physics/7512621