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secondary 3 | A Maths
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Dawn
Dawn

secondary 3 chevron_right A Maths chevron_right Singapore

Please help with this question. Thank you!

Date Posted: 5 days ago
Views: 9
J
J
5 days ago
sin 3A

= sin (2A + A)

= sin 2A cos A + cos 2A sin A

= (2 sin A cos A) cos A + (1 - 2 sin²A) sin A

= 2 sin A cos² A + sin A - 2 sin³ A

= 2 sin A (1 - sin² A) + sin A - 2 sin³ A

= 2 sin A - 2 sin³ A + sin A - 2 sin³ A

= 3 sin A - 4 sin³ A

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TIEW KAI JIE NICHOLAS
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