MathematicsMedium45×since 2004Q5649If 5(tan2x−cos2x)=2cos2x+95\left( {{{\tan }^2}x - {{\cos }^2}x} \right) = 2\cos 2x + 95(tan2x−cos2x)=2cos2x+9, then the value of cos4x\cos 4xcos4x is :A13{1 \over 3}31B29{2 \over 9}92C−79- {7 \over 9}−97D−35- {3 \over 5}−53Check answerSkip