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AP EAMCET · Maths · Trigonometric Equations

If the identity cos4θ=acos4θ+bcos2θ+c holds for some a,b,c, then a,b,c=

  1. A 18,38,12
  2. B 18,12,38
  3. C 12,18,38
  4. D 12,38,18
Verified Solution

Answer & Solution

Correct Answer

(B) 18,12,38

Step-by-step Solution

Detailed explanation

Given cos4θ=acos4θ+bcos2θ+c L.H.S.=cos4θ=12+cos2θ22 =14+12cos2θ+14cos22θ =14+12cos2θ+1412+cos4θ2 =18cos4θ+12cos2θ+38