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In the following questions, two statements (i) and (ii) are given. Choose the valid statement. (i) tan 45° + cot 45° = 2 (ii) sin 20° – cos 70° = 0 - Mathematics

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Question

In the following questions, two statements (i) and (ii) are given. Choose the valid statement.

(i) tan 45° + cot 45° = 2

(ii) sin 20° – cos 70° = 0

Options

  • Only (i)

  • Only (ii)

  • Both (i) and (ii)

  • Neither (i) nor (ii)

MCQ
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Solution

Both (i) and (ii)

Explanation:

(i) tan 45° = 1 and cot 45° = 1.

So, tan 45° + cot 45°

= 1 + 1 

= 2

(ii) cos 70° = sin 20° 

Since cos (90° – θ) = sin θ. 

So, sin 20° – cos 70°

= sin 20° – sin 20°

= 0

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Chapter 18: Trigonometric Ratios of Some Standard Angles and Complementary Angles - Exercise 18D [Page 382]

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Nootan Mathematics [English] Class 9 ICSE
Chapter 18 Trigonometric Ratios of Some Standard Angles and Complementary Angles
Exercise 18D | Q 2. | Page 382
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