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Ex 8.4

Ex 8.4, 1

Ex 8.4, 2 Important

Ex 8.4, 3 (i) Important

Ex 8.4, 3 (ii)

Ex 8.4, 4 (i) [MCQ]

Ex 8.4, 4 (ii) [MCQ] Important You are here

Ex 8.4, 4 (iii) [MCQ] Important

Ex 8.4, 4 (iv) [MCQ]

Ex 8.4, 5 (i) Important

Ex 8.4, 5 (ii)

Ex 8.4, 5 (iii) Important

Ex 8.4, 5 (iv) Important

Ex 8.4, 5 (v) Important

Ex 8.4, 5 (vi)

Ex 8.4, 5 (vii) Important

Ex 8.4, 5 (viii)

Ex 8.4, 5 (ix) Important

Ex 8.4, 5 (x)

Chapter 8 Class 10 Introduction to Trignometry

Serial order wise

Last updated at Aug. 11, 2021 by Teachoo

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Ex 8.4, 4 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 ) = (1 + 2 cos𝜃 sin𝜃 − 1)/(cos𝜃 sin𝜃 ) = (2 cos𝜃 sin𝜃)/(cos𝜃 sin𝜃 ) = 2 Answer = 2 Hence, option (B) is correct.