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Example 12 - Express cos A, tan A and sec A in terms of sin A - Expressing ratios in other ratios

Example 12 - Chapter 8 Class 10 Introduction to Trignometry - Part 2

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Example 9 Express the ratios cos A, tan A and sec A in terms of sin A. cos A Since, cos2 A + sin2 A = 1 cos2 A = 1 – sin2 A cos A = ±√(1 βˆ’π‘ π‘–π‘›2 𝐴) Here, A is acute (i.e. less than 90Β°) & cos A is positive when A is acute So, cos A = √(1 βˆ’π‘ π‘–π‘›2 𝐴) sec A sec A = 𝟏/πœπ¨π¬β‘γ€– 𝑨〗 sec A = 1/√(1 βˆ’π‘ π‘–π‘›2 𝐴) tan A We know that tan A = π’”π’Šπ’β‘γ€– 𝑨〗/𝒄𝒐𝒔⁑〖 𝑨〗 Putting value of cos A tan A = sin⁑〖 𝐴〗/√(1 βˆ’ 𝑠𝑖𝑛2 𝐴)

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Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.