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Sin2โก๐œƒ/cos2โก๐œƒโˆ’1/cos2โก๐œƒ=๐‘ฅ. Statement (1): x = 1. Statement (2): ๐‘ฅ=sin2โก๐œƒโˆ’1/cos2โก๐œƒ=โˆ’cos2โก๐œƒ/cos2โก๐œƒ=โˆ’1

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Question

\[\frac{\sin^2 \theta}{\cos^2 \theta} - \frac{1}{\cos^2 \theta} = x.\]

Statement (1): x = 1.

Statement (2): \[x = \frac{\sin^2 \theta - 1}{\cos^2 \theta} = \frac{-\cos^2 \theta}{\cos^2 \theta} = -1\]

Options

  • Both the statements are true.

  • Both the statements are false.

  • Statement 1 is true, and statement 2 is false.

  • Statement 1 is false, and statement 2 is true.

MCQ
Assertion and Reasoning
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Solution

Statement 1 is false, and statement 2 is true.

Explanation:

Given, \[\frac{\sin^2 \theta}{\cos^2 \theta} - \frac{1}{\cos^2 \theta} = x\]

\[\Rightarrow x = \frac{\sin^2 \theta}{\cos^2 \theta} - \frac{1}{\cos^2 \theta}\]

\[\Rightarrow x = \frac{\sin^2 \theta - 1}{\cos^2 \theta}\]

\[\Rightarrow x = \frac{\sin^2 \theta - (\sin^2 \theta + \cos^2 \theta)}{\cos^2 \theta}\]

\[\Rightarrow x = \frac{\sin^2 \theta - \sin^2 \theta - \cos^2 \theta}{\cos^2 \theta}\]

\[\Rightarrow x = \frac{-\cos^2 \theta}{\cos^2 \theta}\]

\[\Rightarrow x = -1\]

∴ Statement 1 is false, and statement 2 is true.

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Chapter 21: Trigonometrical Identities - TEST YOURSELF [Page 341]

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Selina Concise Mathematics [English] Class 10 ICSE
Chapter 21 Trigonometrical Identities
TEST YOURSELF | Q 1. (p) | Page 341
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