JEE Advance - Mathematics (1996 - No. 6)
A nonzero vector $$\overrightarrow a $$ is parallel to the line of intersection of the plane determined by the vectors $$\widehat i,\widehat i + \widehat j$$ and the plane determined by the vectors $$\widehat i - \widehat j,\widehat i + \widehat k.$$ The angle between $$\overrightarrow a $$ and the vector $$\widehat i - 2\widehat j + 2\widehat k$$ is ................
$$\frac{\pi}{6}$$
$$\frac{\pi}{3}$$
$$\frac{\pi}{4}$$
$$\frac{3\pi}{4}$$
$$\frac{\pi}{2}$$