Last updated at Dec. 8, 2016 by Teachoo

Transcript

Example 3 Consider ACB, right-angled at C, in which AB = 29 units, BC = 21 units and ABC = (see fig.). Determine the values of (i) cos2 + sin2 , Step1 : Finding sides of triangle In right triangle ABC, using Pythagoras theorem (Hypotenuse)2 = (Height)2 + (Base)2 AB2 = AC2 + BC2 AC2 = AB2 BC2 AC2 = (29)2 (21)2 Using a2 b2 = (a + b) (a b) AC2 = (29 21) (29 + 21) AC2 = (8) (50) AC = (8 50) AC = 400 AC = 20 Step 2 : Finding sin , cos We have to find out , cos2 + sin2 Putting values = (21/29)^2+(20/29)^2 = ((21)2 + (20)2)/292 = (441 + 400)/841 = 841/841 = 1 So, cos2 + sin2 = 1 Example 3 Consider ACB, right-angled at C, in which AB = 29 units, BC = 21 units and ABC = (see fig.). Determine the values of (ii) cos2 sin2 . cos2 sin2 Putting values = (21/29)^2 (20/29)^2 = ((21)2 (20)2)/292 Using a2 b2 = (a + b) (a b) = ((21 + 20)(21 20))/292 = ((41)(1))/841 = 41/841

Examples

Example 1

Example 2 Important

Example 3 You are here

Example 4

Example 5

Example 6 Important

Example 7 Important

Example 8

Example 9 Deleted for CBSE Board 2022 Exams

Example 10 Important Deleted for CBSE Board 2022 Exams

Example 11 Important Deleted for CBSE Board 2022 Exams

Example 12

Example 13 Important

Example 14 Important

Example 15 Important

Chapter 8 Class 10 Introduction to Trignometry (Term 1)

Serial order wise

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.