Example 9 - Chapter 8 Class 10 Introduction to Trignometry

Last updated at April 16, 2024 by

Slide23.JPG

Slide24.JPG

Go Ad-free

Transcript

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)

Davneet Singh's photo - Co-founder, Teachoo

Made by

Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science and Computer Science at Teachoo