NCERT Solutions for Class 10 Maths Exercise 8.2 Chapter 8 Introduction to Trigonometry – FREE PDF Download
NCERT Class 10 Maths Ch 8 is one of the most important ones in the NCERT syllabus. Duly following NCERT Solutions for Class 10 Maths
Chapter 8 ensures you that there will be no hindrance when you opt for more advanced branches of Maths. This is where CoolGyan comes in. Our free Class 10 Introduction to Trigonometry solutions will help you understand the chapter thoroughly.
NCERT Solutions for Class 10 Maths Chapter 8 – Introduction to Trigonometry
1. Evaluate:
(i) 
(ii) 
(iii) 
(iv) 
(v) 
= 
= 
=1
(ii)
= 
= 
= 2
(iii)
= 
= 
= 
= 
= 
= 
[Since (a+b)(a−b)=a2−b2(a+b)(a−b)=a2−b2]
= 
= 
(iv)
= 
= 
= 
= 
= 
[Since (a+b)(a−b)=a2−b2(a+b)(a−b)=a2−b2]
= 
(v)
= 
= 
= 54+163−14454+163−144
= 15+64−121215+64−1212= 
2. Choose the correct option and justify:
(i) 
=
(A) 
(B) 
(C) 
(D) 
(ii) 
=
(A) 
(B) 1
(C) 
(D) 0
(iii) 
is true when A =
(A) 
(B) 
(C) 
(D) 
(iv) 
=
(A)
(B)
(C)
(D) None of these
= 
= 
= 
=
(ii) (D) = 
= 
= 0
(iii) (A) Since A = 0, then
and 
= 
when A = 0
(iv) (C)
= 
= 
= 
= 
3. If 
and 
find A and B.
A + B = ……….(i)
Also, 
A – B = ……….(ii)
On adding eq. (i) and (ii), we get,
2A = 
A =
On Subtracting eq. (i) and eq. (ii), we get
2B = B = 
4. State whether the following are true or false. Justify your answer.
(i) 
(ii) The value of 
increases as 
increases.
(iii) The value of 
increases as increases.
(iv) 
for all values of 
(v) 
is not defined for 
Then, 
= 1
And 
= 
(ii) True, because it is clear from the table below:
Therefore, it is clear, the value of increases as increases.
(iii) False, because
It is clear, the value of decreases as increases
(iv) False as it is only true for 
(v) True, because 
and 
= 
i.e. undefined.