If the magnitude of sum of two vectors is equal to the magnitude of different of the two vectors. The angle between these vectors is

Explanation

Let the two vectors by `vec(A) + vec(B)` inclined at an angle theta ,
`| vec(A) + vec(B)| = sqrt(A^(2)+B^(2) +2A cos theta )`
`| vec(A) - vec(B) | = sqrt(A^(2) +B^(2) - 2AN cos theta ) ….(ii)`