Physics - Vectors Question with Solution | TestHub

Vectors(A + B) and(A – B)are at right angle to each other, therefore
$\left(A+B\right).\left(A-B\right)=0$
$A.A+B.A-A.B-B.B=0$
$\left|A\right|+BA\mathrm{c}\mathrm{o}\mathrm{s}\theta -AB\mathrm{c}\mathrm{o}\mathrm{s}\theta -{\left|B\right|}^2=0$
${\left|A\right|}^2={\left|B\right|}^2$
Hence,$\left|A\right|=\left|B\right|$