NDA/NA SOLVED PAPER 2015-II (MATHEMATICS)

Total Questions: 120

21. Solve the following equation

Correct Answer: (a) - 7/17
Solution:

22. Two poles are 10 m and 20 m high. The line joining their tops makes an angle of 15° with the horizontal. The distance between the poles is approximately equal to

Correct Answer: (b) 37.3 in
Solution:

23. If g(x) = 1/f(x) and f(x) = x, x ≠ 0 then which one of the following is correct

Correct Answer: (b)
Solution:f(x) = x, g(x) = 1 / x, Putting these values in the options, only (b) is correct.

24. Consider the following:

Correct Answer: (a) 1 only
Solution:


25. Solve the following equation:


1. |AB| = ± 47
2. AB = BA

Select the correct answer using the code given below

Correct Answer: (a) 1 only
Solution:

26. Solve the following equation

Correct Answer: (b) always positive
Solution:

27. Ifa, b, c are real numbers, then the value of the determinant

Correct Answer: (a) 0
Solution:

28. If the point z 1 =1 + i where i = √-1 is the reflection of a point z₂ = x + iy in the line i¯z - iz = 5, then the point z₂ is

Correct Answer: (a) 1 + 4i
Solution:

29. If sin x + sin y = a and cos x + cos y = b then


Correct Answer: (b)
Solution:

30. A vertical tower standing on a levelled field is mounted with a vertical flag staff of length 3 m. From a point on the field, the angles of elevation of the bottom and tip of the flag staff are 30° and 45° respectively. Which one of the following gives the best approximation to the height of the tower?

Correct Answer: (c) 4.10m
Solution:as ∠CPA = 45º