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


Transcript

Ex 8.1, 5 Given sec θ =13/12, calculate all other trigonometric ratios. Finding cos θ cos θ = 1/sec⁡θ cos θ = 𝟏𝟐/𝟏𝟑 Now, cos θ = 12/13 (𝑠𝑖𝑑𝑒 𝑎𝑑𝑗𝑎𝑐𝑒𝑛𝑡 𝑡𝑜 ∠𝜃)/𝐻𝑦𝑝𝑜𝑡𝑒𝑛𝑢𝑠𝑒 = 12/13 𝑨𝑩/𝑨𝑪=𝟏𝟐/𝟏𝟑 Let AB = 12x AC = 13x Using Pythagoras theorem to find BC (Hypotenuse)2 = (Height)2 + (Base)2 AC2 = AB2 + BC2 (13x)2 = (12x)2 + (BC)2 (BC)2 = (13x)2 − (12x)2 (BC) 2 = 169x2 – 144x2 (BC) 2 = 25x2 BC = √(25𝑥^2 ) BC = √(5^2 𝑥^2 ) BC = 5x Now, finding other ratios sin θ = (𝑠𝑖𝑑𝑒 𝑜𝑝𝑝𝑜𝑠𝑖𝑡𝑒 𝑡𝑜 ∠𝜃)/𝐻𝑦𝑝𝑜𝑡𝑒𝑛𝑢𝑠𝑒 = 𝐵𝐶/𝐴𝐶 = 5𝑥/13𝑥 = 𝟓/𝟏𝟑 tan θ = (𝑠𝑖𝑑𝑒 𝑜𝑝𝑝𝑜𝑠𝑖𝑡𝑒 𝑡𝑜 ∠𝜃)/(𝑠𝑖𝑑𝑒 𝑎𝑑𝑗𝑎𝑐𝑒𝑛𝑡 𝑡𝑜 ∠𝜃) = 𝐵𝐶/𝐴𝐵 = 5𝑥/12𝑥 = 𝟓/𝟏𝟐 cosec 𝛉 = 1/sin⁡θ = 1/((5/13) ) = 𝟏𝟑/𝟓 cot θ = 1/tan⁡θ = 1/((5/12) ) = 𝟏𝟐/𝟓

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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.