**NDA Mathematics paper set 2**

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If p^{2}, q^{2} and r^{2} (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 :

2

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

3

If sin x + sin y = cos y – cos x, where

4

What is sin(α + 1o) + cos(β + 1o) equal to?

5

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

6

What is the value of sin α + cos β?

7

.What is t_{1}^{2}-t_{2}^{2 }equal to?

8

.What is t_{1}^{2}-t_{2}^{2 }equal to?

9

What is equal to?

10

What is equal to?

11

.What is equal to?

12

What is tan^{2} x equal to?

13

.What is the equation of the plane which cuts an intercept 5 units on the z-axis and is parallel to xy-plane?

14

Into how many compartments do the coordinate planes divide the space?

15

If a line has direction ratios < a + b, b + c, c + a >, then what is the sum of the square of its direction cosines?

16

.What is the length of the diameter of the sphere whose centre is at (1, -2, 3) and which touches the plane 6x – 3y + 2z – 4 = 0?