cos 2x=Acos²x - sin²xB1 - 2sin²xC2cos²x - 1Dഇവയെല്ലാംAnswer: D. ഇവയെല്ലാം Read Explanation: cos 2x = cos²x - sin²x cos 2x = 1 - 2sin²x cos 2x = 2cos²x - 1 cos2x = 1 - tan²x / 1 + tan²xRead more in App