$\overrightarrow{A}\text{and}\overrightarrow{B}$ are two vectors. Then correct options are       

$\left|\overrightarrow{A}+\overrightarrow{B}\right|=\left|\overrightarrow{A}-\overrightarrow{B}\right|=\sqrt{A^2+B^2}if\theta =90°$ 

$\text{If}\left(\overrightarrow{A}+\overrightarrow{B}\right)\perp \left(\overrightarrow{A}-\overrightarrow{B}\right)\text{then}\text{A}=\text{B}\&\left|\overrightarrow{A}-\overrightarrow{B}\right|=2\text{A}\sin \frac{\theta }{2}$ need not zero

$\text{then}\left(\overrightarrow{A}+\overrightarrow{B}\right).\left(\overrightarrow{A}-\overrightarrow{B}\right)=0$

If angle between$\overrightarrow{A}+\overrightarrow{B}\&\overrightarrow{A}-\overrightarrow{B}\text{is}60°,$  The resultant of

$\overrightarrow{A}+\overrightarrow{B}\text{and}\overrightarrow{A}-\overrightarrow{B}\text{is}2\overrightarrow{A}$

Only A & D are correct