BITSAT2011MathematicsVector AlgebraActual
Two vectors ( A ) and ( B ) are such that (| A + B |=| A - B | ). The angle between the two vectors will be-
Options
- A(60^ )
- B(90^ )
- C(180^ )
- D(0^ )
Correct answer
B. (90^ )
Step-by-step solution
( A + B |=| A - B ) ( A ^2+ B ^2+2 AB = A ^2+ B ^2-2 AB ) Squaring both the sides, we get ( A ^2+ B ^2+2 A B = A ^2+ B ^2-2 A B ) or (4 A B =0 ) or ( =0 ) (since the scalar or dot product is zero). Therefore angle between ( A ) to ( B ) is (90^ )