© examsiri.com
Question : 112 of 160
Marks:
+1,
-0
Solution:
We know that,
‌r=4Rsin‌‌sin‌‌sin‌‌‌r1=4Rsin‌‌‌cos‌‌cos‌‌r2=4Rsin‌‌‌cos‌‌cos‌‌r3=4Rsin‌‌‌cos‌‌cos‌Given that,
‌r3=r1+r2+r‌⇒‌‌r3−r=r1+r2‌⇒4Rsin‌‌(cos‌‌cos‌−sin‌‌sin‌‌)‌=4R‌cos‌[sin‌‌‌cos‌+cos‌sin‌‌]‌⇒‌‌sin‌‌(cos(‌))=cos‌(sin‌(‌))‌⇒sin‌‌(cos(‌−‌))=cos‌(sin‌(‌−‌))‌[∵A+B+C=π⇒‌+‌=‌−C]‌⇒‌‌sin‌2‌=cos2‌‌⇒‌‌tan‌=1⇒‌‌‌=‌⇒C=‌We know that,
A+B+C=π⇒A+B=π−‌⇒A+B=‌
© examsiri.com
Go to Question: