Last updated at Aug. 11, 2021 by

Transcript

Ex 8.4, 5 Prove the following identities, where the angles involved are acute angles for which the expressions are defined. (sin A + cosec A)2 + (cos A + sec A)2 = 7 + tan2 A + cot2 A Taking L.H.S (sin A + cosec A)2 + (cos A + sec A)2 = (sin2 A + cosec2 A + 2sin A cosec A) + (cos2 A + sec2 A + 2 cos A . sec A) = (sin2 A + cosec2 A + 2sin A . 1/sin ) + (cos2 A + sec2 A + 2 cos A.1/cos ) = (sin2 A + cosec2 A + 2) + (cos2 A + sec2 A + 2) = (sin2 A + (1 + cot2 A) +2) + (cos2 A +(1 + tan2 A) + 2) = sin2 A + cos2 A + 1 + cot2 A + 2 + 1 + tan2 A + 2 = (sin2 A + cos2 A) + cot2 A + tan2 A + (1 + 2 + 1 + 2) = 1 + cot2 A + tan2 A + 6 = 7 + cot2 A+ tan2 A = R.H.S Hence proved

Ex 8.4

Ex 8.4, 1

Ex 8.4, 2 Important

Ex 8.4, 3 (i) Important

Ex 8.4, 3 (ii)

Ex 8.4, 4 (i) [MCQ]

Ex 8.4, 4 (ii) [MCQ] Important

Ex 8.4, 4 (iii) [MCQ] Important

Ex 8.4, 4 (iv) [MCQ]

Ex 8.4, 5 (i) Important

Ex 8.4, 5 (ii)

Ex 8.4, 5 (iii) Important

Ex 8.4, 5 (iv) Important

Ex 8.4, 5 (v) Important

Ex 8.4, 5 (vi)

Ex 8.4, 5 (vii) Important

Ex 8.4, 5 (viii) You are here

Ex 8.4, 5 (ix) Important

Ex 8.4, 5 (x)

About the Author

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 10 years. He provides courses for Maths and Science at Teachoo.