# Misc 20 - Chapter 5 Class 12 Continuity and Differentiability

Last updated at May 29, 2018 by Teachoo

Last updated at May 29, 2018 by Teachoo

Transcript

Misc 20 Using the fact that sin ( + )=sin cos +cos sin and the differentiation, obtain the sum formula for cosines. Given sin ( + )=sin cos +cos sin Consider A & B are function of Differentiating both side . . . . sin + = sin cos + cos sin sin + = sin . cos + cos . sin cos + . + = sin . cos + cos . sin cos + . + = sin . cos + cos A + cos . + sin . os A = cos . . cos B sin . sin sin . . sin + cos . . os A = cos . . cos B sin . B sin . . + cos B . . os A = cos cos sin sin + sin sin + cos cos = cos cos sin sin + Thus, cos + . + = cos cos sin sin + cos + . + + = cos cos sin sin cos + = cos cos + sin sin Hence proved

Miscellaneous

Misc 1

Misc 2

Misc 3

Misc 4

Misc 5 Important

Misc 6 Important

Misc 7 Important

Misc 8

Misc 9 Important

Misc 10

Misc 11 Important

Misc 12

Misc 13 Important

Misc 14 Important

Misc 15 Important

Misc 16 Important

Misc 17 Important

Misc 18

Misc 19 Important

Misc 20 You are here

Misc 21

Misc 22

Misc 23 Important

About the Author

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.