Last updated at Aug. 11, 2021 by Teachoo

Transcript

Ex 10.2, 18 In triangle ABC (Fig 10.18),which of the following is not true (A) (π΄π΅) β + (π΅πΆ) β + (πΆπ΄) β= 0 β (B) (π΄π΅) β + (π΅πΆ) β β (π΄πΆ) β= 0 β (C) (π΄π΅) β + (π΅πΆ) β β (πΆπ΄) β= 0 β (D) (π΄π΅) β β (πΆπ΅) β + (πΆπ΄) β= 0 β In Ξ ABC, (π΄πΆ) β is the resultant of (π΄π΅) β & (π΅πΆ) β (π΄πΆ) β = (π΄π΅) β + (π΅πΆ) β (π΄π΅) β + (π΅πΆ) β = (π΄πΆ) β (π΄π΅) β + (π΅πΆ) β β (π΄πΆ) β = 0 β Checking part (A) (π¨π©) β + (π©πͺ) β + (πͺπ¨) β= π β From (1) (π΄π΅) β + (π΅πΆ) β β (π΄πΆ) β = 0 β (π΄π΅) β + (π΅πΆ) β β (β(πΆπ΄) β) = 0 β (π΄π΅) β + (π΅πΆ) β + (πΆπ΄) β = 0 β Hence, (A) is true. Checking part (B) (π¨π©) β + (π©πͺ) β β (π¨πͺ) β= π β From (1) (π΄π΅) β + (π΅πΆ) β β (π΄πΆ) β = 0 β Hence, (B) is true. Checking part (C) (π¨π©) β + (π©πͺ) β β (πͺπ¨) β= π β From (1) (π΄π΅) β + (π΅πΆ) β β (π΄πΆ) β = 0 β (π΄π΅) β + (π΅πΆ) β β (β(πΆπ΄) β) = 0 β (π΄π΅) β + (π΅πΆ) β + (πΆπ΄) β = 0 β Hence, (C) is not true. Checking part (D) (π¨π©) β β (πͺπ©) β + (πͺπ¨) β= π β From (1) (π΄π΅) β + (π΅πΆ) β β (π΄πΆ) β = 0 β (AB) β β (CB) β + (CA) β = 0 β Hence, (D) is true. Thus, (C) is the correct option

Ex 10.2

Ex 10.2, 1

Ex 10.2, 2

Ex 10.2, 3 Important

Ex 10.2, 4

Ex 10.2, 5 Important

Ex 10.2, 6

Ex 10.2, 7 Important

Ex 10.2, 8

Ex 10.2, 9

Ex 10.2, 10 Important

Ex 10.2, 11 Important

Ex 10.2, 12

Ex 10.2, 13 Important

Ex 10.2, 14

Ex 10.2, 15 Important

Ex 10.2, 16

Ex 10.2, 17 Important

Ex 10.2, 18 (MCQ) Important You are here

Ex 10.2, 19 (MCQ) Important

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.