A bird is sitting on the top of a vertical pole 20m high and its elevation from a point O on the ground is 45∘ , it flies off horizontally straight away from the point O. After one second, the elevation of the bird from O is reduced to 30∘ , then the speed (in m/s) of the bird is A.40(2–√−1)B.40(3–√−2–√)C.202–√D.20(3–√−1)

How do you find the Maclaurin series for tanx?

Why is Axiom 5, in the list of Euclid’s axioms, considered a ‘universal truth’? (Note that the equation is not about the fifth postulate.)

The smallest composite number is ______.

(a) 2

(b) 4

(c) 1

(d) None of these

Find the arithmetic mean of the first ten odd natural numbers.

A boat goes 24 km upstream and 28 km downstream in 6 hours. It goes 30 km upstream and 21 km downstream in 6 hours and 30 minutes. The speed of the boat in still water is

A. 10 km/hr

B. 4 km/hr

C. 14 km/hr

D. 6 km/hr