Ex 8.3

Chapter 8 Class 10 Introduction to Trignometry
Serial order wise

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### Transcript

Ex 8.3, 1 Express the trigonometric ratios sin A, sec A and tan A in terms of cot A. tan A We know that tan A = π/πππβ‘π¨ cosec A We know that 1 + cot2 A = cosec2 A cosec2 A = 1 + cot2 A cosec A = Β± β(1+πππ‘2 π΄) Here, A is acute (i.e. less than 90Β°) & cosec A is positive when A is acute So, cosec A = β(1+πππ‘2 π΄) sin A sin A = π/(πππππ π¨) Putting value of cosec A found above sin A = 1/(β(1 + πππ‘2 π΄) ) Sec A We know that 1 + tan2 A = sec2 A sec2 A = 1 + tan2 A sec A = Β± β((1+π‘ππ2 π΄)) Here, A is acute (i.e. less than 90Β°) & sec A is positive when A is acute sec A = β((1+π‘ππ2 π΄)) sec A = β((1+1/(πππ‘2 π΄))) sec A = β(((πππ‘2 π΄ + 1)/(πππ‘2 π΄)) ) sec A = β(πππ‘2 π΄ + 1)/cotβ‘π΄

#### 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.