# CBSE Class 10-Mathematics: Chapter –8 Introduction to Trigonometry Part 5

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**Question 6:**

State whether the following are true or false. Justify your answer.

(i) The value of is always less than 1.

(ii) for some value of angle A.

(iii) is the abbreviation used for the cosecant of angle A.

(iv) is the product of and A.

(v) or some angle

**Answer:**

__(i) False__ because sides of a right triangle may have any length, so may have any value.

(ii) True as is always greater than 1.

(iii) False as is the abbreviation of cosine A.

(iv) False as is not the product of ‘cot’ and A. ‘cot’ is separated from A has no meaning.

(v) False as cannot be

**Question 7:**

Evaluate:

(i)

(ii)

(iii)

(iv)

**Answer:**

Solution:

(i)

(ii)

(iii)

(iv)

**Question8:**

Show that

(i)

(ii)

**Answer:**

(i)

(ii)

**Question9:**

If , where is an acute angle, find the value of .

**Answer:**

Given: