1. The coordinates of the midpoints of the line segment joining the points (2, 3, 4) and (8, -3, 8) are

2. The direction cosines of the normal to the plane 2x – 3y – 6z – 3 = 0 are

3. If 2x + 5y – 6z + 3 = 0 be the equation of the plane, then the equation of any plane parallel to the given plane is

4. (2, – 3, – 1) 2x – 3y + 6z + 7 = 0

5. The length of the ⊥

6. The shortest distance between the lines \(\vec{r}\) = \(\vec{a}\) + k\(\vec{b}\) and r = \(\vec{a}\) + l\(\vec{c}\) is (\(\vec{b}\) and \(\vec{c}\) are non-collinear)

7. The equation xy = 0 in three dimensional space is represented by

8. The direction cosines of any normal to the xy plane are

9. How many lines through the origin in make equal angles with the coordinate axis?

10. The direction cosines of the line joining (1, -1, 1) and (-1, 1, 1) are