CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon


Question

In a triangle ABC , 2(b cos2C2+c cos2B2) is equal to - 
 
  1. a + b + c
  2. a2+b2+c2
  3. a.b.c
  4. None of these


Solution

The correct option is A a + b + c
We know that cos(2θcos2(θ)1
2(b cos2C2+c cos2B2)
=b2.cos2C2+c2.cos2B2
=b.(cos C+1)+c.(cos B+1)
=b.cos C+c.cosB+b+c
From projection formula we know, 
b.cos C + c. cos B =  a  
So, 2(b cos2C2+c cos2B2)=a+b+c

flag
 Suggest corrections
thumbs-up
 
0 Upvotes


Similar questions
View More


People also searched for
View More



footer-image