Tzu En's answer to Lee's Secondary 3 A Maths Singapore question.

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Tzu En
Tzu En's answer
134 answers (Tutor Details)
1st
Pretty straightforward, just expand then you can easily see sin²x + cos²x, which equals to 1. 2sinxcosx equals to sin2x. Good to have the formulas at the side when doing this kind of question.