हिंदी

1 − sin⁡𝐴/cos⁡𝐴 = sec⁡𝐴 − tan⁡𝐴. Statement (1): 1−sin⁡𝐴/cos⁡𝐴 = sec⁡𝐴 − tan⁡𝐴 ⇒ 1 + sin⁡𝐴/cos⁡𝐴 = sec⁡𝐴 + tan⁡𝐴 Statement (2): 1 − sin⁡𝐴/cos⁡𝐴−1 + sin⁡𝐴/cos⁡𝐴 = 2⁢sec⁡𝐴

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प्रश्न

\[\frac{1 - \sin A}{\cos A} = \sec A - \tan A.\]

Statement (1): \[\frac{1 - \sin A}{\cos A} = \sec A - \tan A\]

\[\Rightarrow \frac{1 + \sin A}{\cos A} = \sec A + \tan A\]

Statement (2): \[\frac{1 - \sin A}{\cos A} - \frac{1 + \sin A}{\cos A} = 2\sec A\]

विकल्प

  • 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
अभिकथन और तर्क
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उत्तर

Statement 1 is true, and statement 2 is false.

Explanation:

Given, \[\frac{1 - \sin A}{\cos A} = \sec A - \tan A\]

Taking L.H.S.

\[\Rightarrow \frac{1 - \sin A}{\cos A}\]

\[\Rightarrow \frac{1}{\cos A} - \frac{\sin A}{\cos A}\]

\[\Rightarrow \sec A - \tan A\]

As, L.H.S. = R.H.S., so equation is true.

Now, \[\frac{1 + \sin A}{\cos A} = \sec A + \tan A\]

Taking L.H.S.

\[\Rightarrow \frac{1 + \sin A}{\cos A}\]

\[\Rightarrow \frac{1}{\cos A} + \frac{\sin A}{\cos A}\]

\[\Rightarrow \sec A + \tan A\]

As, L.H.S. = R.H.S., so equation is true.

So, statement 1 is true.

Now, \[\frac{1 - \sin A}{\cos A} - \frac{1 + \sin A}{\cos A} = 2\sec A\]

Solving L.H.S.

\[\Rightarrow \frac{1 - \sin A}{\cos A} - \frac{1 + \sin A}{\cos A}\]

\[\Rightarrow \frac{1}{\cos A} - \frac{\sin A}{\cos A} - \left(\frac{1}{\cos A} + \frac{\sin A}{\cos A}\right)\]

⇒ (sec A − tan A) − (sec A + tan A)

⇒ sec A − tan A − sec A v tan A

⇒ −2tan A.

As, L.H.S. ≠ R.H.S.

So, statement 2 is false.

∴ Statement 1 is true and statement 2 is false.

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अध्याय 21: Trigonometrical Identities - TEST YOURSELF [पृष्ठ ३४१]

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सेलिना Concise Mathematics [English] Class 10 ICSE
अध्याय 21 Trigonometrical Identities
TEST YOURSELF | Q 1. (n) | पृष्ठ ३४१
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