Mathematics · JEE | VECTOR ALGEBRA

The unit vector in the direction of vector \( \vec{a} = 3\hat{i} - 4\hat{j} + 12\hat{k} \) is:

1. A
   \( \frac{3}{\sqrt{10}}\hat{i} - \frac{4}{\sqrt{10}}\hat{j} \)
2. B
   \( \frac{3}{5}\hat{i} - \frac{4}{5}\hat{j} \)
3. C
   \( \frac{1}{13}\hat{i} - \frac{2}{13}\hat{j} + \frac{3}{13}\hat{k} \)
4. D
   \( \frac{3}{13}\hat{i} - \frac{4}{13}\hat{j} + \frac{12}{13}\hat{k} \)