# Ex 8.3, 3 (ii) [MCQ] - Chapter 8 Class 10 Introduction to Trignometry

Last updated at April 16, 2024 by Teachoo

Ex 8.3

Ex 8.3, 1

Ex 8.3, 2 Important

Ex 8.3, 3 (i) [MCQ]

Ex 8.3, 3 (ii) [MCQ] Important You are here

Ex 8.3, 3 (iii) [MCQ] Important

Ex 8.3, 3 (iv) [MCQ]

Ex 8.3, 4 (i) Important

Ex 8.3, 4 (ii)

Ex 8.3, 4 (iii) Important

Ex 8.3, 4 (iv) Important

Ex 8.3, 4 (v) Important

Ex 8.3, 4 (vi)

Ex 8.3, 4 (vii) Important

Ex 8.3, 4 (viii)

Ex 8.3, 4 (ix) Important

Ex 8.3, 4 (x)

Question 1 (i) Important

Question 1 (ii)

Last updated at April 16, 2024 by Teachoo

Ex 8.3, 3 Choose the correct option. Justify your choice. (ii) (1 + tan θ + sec θ) (1 + cot θ – cosec θ) (A) 0 (B) 1 (C) 2 (D) –1 (1 + tan θ + sec θ) (1 + cot θ – cosec θ) Writing in terms of sin θ & cos θ = (1+" " sin𝜃/cos𝜃 " + " 1/cos𝜃 " " ) (1+" " cos𝜃/sin𝜃 " − " 1/sin𝜃 " " ) = ((cos𝜃 + sin𝜃 + 1))/cos𝜃 × ((sin𝜃 + cos𝜃 − 1))/sin𝜃 = (({𝐜𝐨𝐬𝜽 + 𝐬𝐢𝐧𝜽 } + 𝟏) ({𝐬𝐢𝐧𝜽 +𝐜𝐨𝐬𝜽 } − 𝟏))/(cos𝜃 sin𝜃 ) = ( (cos𝜃 + sin𝜃 )2 − 12)/(cos𝜃 sin𝜃 ) = (𝒄𝒐𝒔𝟐 𝜽 + 𝒔𝒊𝒏𝟐 𝜽 + 2 cos𝜃 sin𝜃 − 1)/(cos𝜃 sin𝜃 ) As cos2 A + sin2 A = 1 = (𝟏 + 2 cos𝜃 sin𝜃 − 1)/(cos𝜃 sin𝜃 ) = (2 cos𝜃 sin𝜃)/(cos𝜃 sin𝜃 ) = 2 So, the correct answer is (c)