Mathematics NDA/NA SOLVED PAPER 2021-II (01 to 50)

Total Questions: 50

21. The equation 3x² - (k² + 5k) x + 3k² - 5k = 0 has real roots of equal magnitude and opposite sign. Which one of the following is correct?

Correct Answer: (d) No such value of k exists
Solution:

22. If aₙ = n(n!) then what is a₁ + a₂+ a₃ +______+a₁₀ equal to?

Correct Answer: (d) 11! - 1
Solution:

23. If p and q are the non-zero roots of the equation x² + px + q = 0, then how many possible values can q have?

Correct Answer: (c) Two
Solution:

24. equal to?

Correct Answer: (d) -72 Δ
Solution:

25. If 1/(b + c), 1/(c + a), 1/(a + b) are in HP, then Which of the following is/are correct?

1. a, b, c are in AP
2. (b + c)², (c + a)², (a + b)² are in GP
Select the correct answer using the code given below.

Correct Answer: (a) 1 only
Solution:

26. equal to?

Correct Answer: (a) -2I
Solution:

27. Find the value?

Correct Answer: (a) -4
Solution:

28. equal to?

Correct Answer: (a) -1
Solution:

29. Find the value?

Correct Answer: (c) Circle
Solution:

30. Which one of the following is a square root of 2a + 2√(a² + b²), where a, b ∈ R?

Correct Answer: (a)
Solution: