Question

find the angle between the vector A=i+j+k and B = -i-j+2k​

Answer 1

Answer:

As per your question, X is the angle between vectors so: A.B = |A|x|B|x cos(X) = 2i. (3i+4j) = 3x2 =6 |A|x|B|=|2i|x|3i+4j| = 2 x 5 = 10 X = cos-1(A.B/|A|x|B|) X = cos-1(6/10) = 53.13 deg The angle can be 53.13 or 360-53.13 = 306.87.