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TS EAMCET · Maths · Properties of Triangles

In a triangle ABC, if b+c2sin2A2+b-c2cos2A2=K1-cos2A, then K=

  1. A R2
  2. B 2R2
  3. C R
  4. D 2R
Verified Solution

Answer & Solution

Correct Answer

(B) 2R2

Step-by-step Solution

Detailed explanation

L.H.S. =b+c2sin2A2+b-c2cos2A2 =b2+c2+2bcsin2A2+b2+c2+2bccos2A2 =b2+c2sin2A2+cos2A2-2bccos2A2-sin2A2 =b2+c2-2bccosA =a2 ∵cosA=b2+c2-a22bc =4R2sin2A ∵asinA=bsinB=csinC=2R =2R21-cos2A So, K=2R2.