Mathematics (NDA/NA SOLVED PAPER 2019 (I) (51 to 100)

Total Questions: 50

21. What is the derivative of sec²(tan⁻¹x) with respect to x?

Correct Answer: (a) 2x
Solution:

22. If f (x) = log₁₀ (1 + x), then what is 4 f (4) + 5 f (1) - log₁₀ 2 equal to?

Correct Answer: (d) 4
Solution:

23. Find the answer of given equation?

Correct Answer: (b) an odd function
Solution:

24. The domain of the function f defined by f (x) = logₓ 10 is:

Correct Answer: (d)
Solution:

25. Simplify the equation?

Correct Answer: (c) 24
Solution:

26. For r > 0, f (r) is the ratio of perimeter to area of a circle of radius r. Then, f(1) + f(2) is equal to?

Correct Answer: (c) 3
Solution:

27. If f (x) = 3¹ ⁺ ˣ, then f (x) f (y) f (z) is equal to?

Correct Answer: (c) f(x + y + z + 2)
Solution:

28. The number of real roots for the equation x² + 9 |x| + 20 = 0 is:

Correct Answer: (a) zero
Solution:

29. If f (x) = sin(cos x), then f '(x) is equal to?

Correct Answer: (d) (-sin x) cos (cos x)
Solution:

30. Simplify the question?

Correct Answer: (c) [2, 3]
Solution: