joylene allyssa chen's answer to Irah Athirah's Secondary 4 A Maths Singapore question.
… mistake in final answer due to use of incorrect double angle formula for cos
… shud be cos 2x = 2(cos x)^2 -1
… it is good practice to give answer in the same format as the question … this question gives angle in radians so answer should also be in radians.
… shud be cos 2x = 2(cos x)^2 -1
… it is good practice to give answer in the same format as the question … this question gives angle in radians so answer should also be in radians.
Probably a slight transcript error in writing cos 2x = cos^2 x - 1
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