Mathmatics NDA/NA Solved Paper 2020-I (1-50)

Total Questions: 50

21. What is the value of t₁₀ where θ = 45° ?

Correct Answer: (c) 1/16
Solution:


22. What is the value of sin α + cos β?

Let α = β = 15°.

Correct Answer: (d)
Solution:

23. What is the value of sin 7α - cos 7β?

Let α = β = 15°.

Correct Answer: (d)
Solution:

24. What is sin (α + 1°) + cos (β + 1°) equal to?

Let α = β = 15°.

Correct Answer: None of the above
Solution:


25. Solve the following quuestion.

Correct Answer: (c) 1
Solution:

26. If A is a matrix of order 3 × 5 and B is a matrix of order 5 × 3, then the order of AB and BA will respectively be

Correct Answer: (c) 3 × 3 and 5 × 5
Solution:

27. If p² , q² and r² (where p, q, r > 0) are in GP, then which of the following is/are correct ?

(1) p, q and r are in GP.
(2) ln p, ln q and ln r are in AP.
Select the correct answer using the code given below:

Correct Answer: (c) Both 1 and 2
Solution:

28. If cot α and cot β are the roots of the equation 𝓍² - 3𝓍 + 2 = 0, then what is cot (α + β) equal to?

Correct Answer: (b) 1/3
Solution:

29. The roots α and β of a quadratic equation, satisfy the relations α + β = α² + β² and αβ= α² β² . What is the number of such quadratic equations ?

Correct Answer: (c) 3
Solution:


30. What is the argument of the complex number

Correct Answer: (a) 240°
Solution: