Find the values of the trigonometric functions in Exercises 6 to 10. 
10. cot (-15 π / 4)

Solution:

We know that the values of cot x repeat after an interval of 360° or 2 π.

It can be written as

cot - 15 π / 4 = cot [ - 15π/ 4 + 2 × 2 π ] (to make the angle positive, we are adding the multiples of 2π)

As we know that value of cot πis not defined.

⇒ cot - 15 π/ 4 = cot [ - 15 π/ 4 + 4 π ]

⇒ cot - 15 π / 4 = cot [( - 15π + 16 π ) / 4]

⇒ cot - 15 π / 4 = cot [ π/ 4 ]

⇒ cot - 15 π/ 4 = 1 (Using trigonometric table)

NCERT Solutions Class 11 Maths Chapter 3 Exercise 3.2 Question 10

Find the values of the trigonometric functions in Exercises 6 to 10. 10) cot (-15 π / 4)

Summary:

The value of cot - 15π/4 = 1. We know that the values of cot x repeat after an interval of 360° or 2π .