Which of the following relations is true for two unit vector \(\hat{A} \text { and } \hat{B}\) making an angle θ to each other?
1
\(|\hat{A}+\hat{B}|=|\hat{A}-\hat{B}| \tan \frac{\theta}{2}\)
2
\(|\hat{A}-\hat{B}|=|\hat{A}+\hat{B}| \tan \frac{\theta}{2}\)
3
\(|\hat{A}+\hat{B}|=|\hat{A}-\hat{B}| \cos \frac{\theta}{2}\)
4
\(|| \hat{A}-\hat{B}|=| \hat{A}+\hat{B} \left\lvert\, \cos \frac{\theta}{2}\right.\)