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Learn in your speed, with individual attention - Teachoo Maths 1-on-1 Class


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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 โ€“ sin2 A cos A = ยฑโˆš(๐Ÿ โˆ’๐’”๐’Š๐’๐Ÿ ๐‘จ) Here, A is acute (i.e. less than 90ยฐ) & cos A is positive when A is acute So, cos A = โˆš(๐Ÿ โˆ’๐’”๐’Š๐’๐Ÿ ๐‘จ) sec A sec A = 1/cosโกใ€– ๐ดใ€— sec A = ๐Ÿ/โˆš(๐Ÿ โˆ’๐’”๐’Š๐’๐Ÿ ๐‘จ) tan A We know that tan A = ๐‘ ๐‘–๐‘›โกใ€– ๐ดใ€—/๐‘๐‘œ๐‘ โกใ€– ๐ดใ€— Putting value of cos A tan A = ๐’”๐’Š๐’โกใ€– ๐‘จใ€—/โˆš(๐Ÿ โˆ’ ๐’”๐’Š๐’๐Ÿ ๐‘จ)

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Davneet Singh

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.