If , then equals
- 1
1
2
- 2
B.
1
A man 2 m tall walks at a uniform speed of 5 km/h away from a lamp post 6 m high. The rate at which the length of his shadow increases, is
2.5km/h
5km/h
15km/h
If a and b are two vectors of magnitude 2 inclined at an angle 60°, then the angle between a and a + b is
30°
60°
45°
None of these
The angle of elevation of the Sun, when the shadow of the pole is times the height of the pole, is
60°
45°
15°
30°