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AP EAMCET · Maths · Trigonometric Equations

If A+B+C=π,cosB=cosA cosC, then tanA tanC=

  1. A 0
  2. B 1
  3. C 2
  4. D 12
Verified Solution

Answer & Solution

Correct Answer

(C) 2

Step-by-step Solution

Detailed explanation

Given, A+B+C=π Now, cosB=cosAcosC ⇒cosπ-A+C=cosAcosC ⇒-cosA+C=cosAcosC ⇒cosAcosC-sinAsinC=-cosAcosC ⇒sinAsinC=2cosAcosC ⇒tanAtanC=2.