Expressing ratios in other ratios
Expressing ratios in other ratios
Last updated at April 16, 2024 by Teachoo
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 = ยฑโ(๐ โ๐๐๐๐ ๐จ) Here, A is acute (i.e. less than 90ยฐ) & cos A is positive when A is acute So, cos A = โ(๐ โ๐๐๐๐ ๐จ) sec A sec A = 1/cosโกใ ๐ดใ sec A = ๐/โ(๐ โ๐๐๐๐ ๐จ) tan A We know that tan A = ๐ ๐๐โกใ ๐ดใ/๐๐๐ โกใ ๐ดใ Putting value of cos A tan A = ๐๐๐โกใ ๐จใ/โ(๐ โ ๐๐๐๐ ๐จ)