Let and be three vectors. Find the values of x for which the angle between and is acute and the angle between and is obtuse
We know that,
Where, x is the angle between two vectors
Applying for
Since angle between is acute cos x should be greater than 0
x2 – 4 > 0
x > 2 and x < –2
applying for
Since angle between is obtuse cos x should be less than
0
x2 – 9 < 0
x > –3 and x < 3