If tan 2A = cot (A – 18°), where 2A is an acute angle, find the value of A - Mathematics

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If tan 2A = cot (A – 18°), where 2A is an acute angle, find the value of A

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Solution

tan 2A = cot (A – 18°)

cot (90° – 2A) = cot (A – 18°)

(∵ cot (90° – θ) = tan θ)

90° – 2A = A – 18°

3A = 108°

A = 36°

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Chapter 8: Introduction to Trigonometry - Exercise 8.3 [Page 189]

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NCERT Mathematics Class 10
Chapter 8 Introduction to Trigonometry
Exercise 8.3 | Q 3 | Page 189

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