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TS EAMCET · Maths · Properties of Triangles

In a ABC, if b=10acos2C2+ccos2A2=15 and the area of the triangle is 153 sq. units, then cotB2=

  1. A 32
  2. B 12
  3. C 23
  4. D 53
Verified Solution

Answer & Solution

Correct Answer

(D) 53

Step-by-step Solution

Detailed explanation

We have, acos2C2+ccos2A2=15 ⇒a1+cosC2+c1+cosA2=15 ⇒a+c+acosC+ccosA=30 ⇒a+b+c=30 ⇒a+c=20 ⇒s=15    ...1 Now ∆=153=ss-as-bs-c ⇒225×3=15×15-a×5×15-c ⇒ac=84     ...2 also…