Question

If \(\hat{n_1}, \hat{n_2}\)are two unit vectors and \(\theta\) is the angle between them, then \(\cos\frac{\theta}{2}\) is equal to

• A. \(\frac{1}{2}|\hat{n_1}+\hat{n_2}|\)
• B. \(\frac{1}{2}|\hat{n_1}-\hat{n_2}|\)
• C. \(\frac{1}{2}|\hat{n_1}.\hat{n_2}|\)
• D. \(\frac{1\hat{n_1}\times\hat{n_2}}{2|\hat{n_1}||\hat{n_2}|}\)

Answer 1

The Correct Option is A

The correct answer is(A): \(\frac{1}{2}|\hat{n_1}+\hat{n_2}|\)