If a,b are unit vectors such that the vector a + 3b is perpendicular to 7a - 5b then the angle between a and b is

If a and b are two unit vectors such that a+2b and 5a−4b are perpendicular to each other, then the angle between a and b is

Let a and b be two unit vectors. If the vectors c = a + 2b and d = 5a - 4b are perpendicular to each other, then the angle between a and b is

If vec a and vec b are two unit vectors such that vec a+vec b is also a unit vector then find the angle between vec a and vec b

If a,b,c are unit vectors satisfying the relation a + b+sqrt(3) c = 0 , then the angle between a and b is

If vec a and vec b are two unit vectors such that vec a+vec b is also a unit vector,then find the angle between vec a and vec b.

If vec a and vec b be two unit vectors such that vec a+ vec b is also a unit vector, then find the angle between vec a and vec b

If a,b,c are three unit vectors such that a xx (b xx c) = (1)/(2) b then the angles between a,b and a,c are