Question

Please Answer fast in details

Answer 1

A = B = P+Q = P-O ---------- (1)
A = P + Q
on squaring both sides,
(A)^2 = (P + Q)^2
          = P^2 + Q^2 +2PQ     ---------- (2)
 B^2 = (P-Q)^2
        = P^2 + Q^2 - 2PQ       ------------(3)
 by substituing the valuse of eq. 2 &3 in eq.1
   P^2 + Q^2 +2 PQ = P^2 + Q^2 - 2PQ
     4 PQ = 0
  as  P and Q are perpendicular their angle in between is 90 degrees.
 cos(90) is 0

    the vector diagram is a triangle.