Class 10 NCERT Solutions Maths Chapter 8 - Introduction to Trigonometry
Ex. 8.1
Ex. 8.2
Ex. 8.3
Introduction to Trigonometry Exercise Ex. 8.1
Solution 1
In 
ABC by applying Pythagoras theorem
AC2 = AB2 + BC2
= (24)2 + (7)2
= 576 + 49
= 625
AC = 
= 25 cm 
Solution 2
Solution 3
Solution 4
Solution 5
Solution 6
Since 
A and B are acute angles, then C is a right angle.
cos A = cos B .... given
AC/AB = BC/AB
AC = BC
B =A .... angles opposite to equal sides are equal in length.
Solution 7
Solution 8
Solution 9
Solution 10
Solution 11
Introduction to Trigonometry Exercise Ex. 8.2
Solution 1
Solution 2
Solution 3
Solution 4
Introduction to Trigonometry Exercise Ex. 8.3
Solution 1
We know that 
Solution 2
We know that 
Solution 3
(i) 9sec2A - 9tan2A
= 9(sec2A - tan2A)
= 9 (1) (as sec2A - tan2A = 1)
= 9
Hence alternative (B) is correct.
(ii) (1 + tanθ + secθ) (1 + cotθ - cosecθ) 
Hence alternative (C) is correct.
(iii) (secA + tanA) (1 - sinA) 
(iv)
Solution 4
