## Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (4th Edition)

The required vector is $(0.707~\hat{i}+0.707~\hat{j})$
The vector ($\hat{i}+\hat{j}$) points at a $45^{\circ}$ angle above the positive x-axis. The vectors which point in this direction have the form $(k\hat{i}+k\hat{j})$ for some positive constant $k$. Therefore, $\sqrt{k^2+k^2} = 1$ $\sqrt{2k^2} = 1$ $k = \frac{1}{\sqrt{2}}$ $k = 0.707$ This means that the required vector is $(0.707~\hat{i}+0.707~\hat{j})$.