Discussion Forum

 The vectors (A+B) and (A-B)  are at right angles to each other. This is possible under the condition

Answer:

Explanation:

 Vectors (A+B) and (A-B) are at right angle to each other , therefore

 (A+B).(A-B)=0

 A.A+B.A-A.B-B.B=0

 |A|+  BA cos $\theta$- AB cos $\theta$ -|B|²=0

   |A|²=|B| ²

 Hence , |A|= | B|