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secondary 4 | A Maths
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Pls help with part b) as soon as possible
Date Posted: 4 years ago
Views: 467
Express cos³ 2x in another form
cos³ 2x
= cos² 2x cos 2x
= (1 - sin² 2x) cos 2x
= cos 2x - sin² 2x cos 2x
So ∫ cos³ 2x dx
= ∫ (cos 2x - sin² 2x cos 2x) dx
= ∫ cos 2x dx - ∫ sin² 2x cos 2x dx
Now you can directly integrate the expression
cos³ 2x
= cos² 2x cos 2x
= (1 - sin² 2x) cos 2x
= cos 2x - sin² 2x cos 2x
So ∫ cos³ 2x dx
= ∫ (cos 2x - sin² 2x cos 2x) dx
= ∫ cos 2x dx - ∫ sin² 2x cos 2x dx
Now you can directly integrate the expression
See 1 Answer
done
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clear
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U can split cos cubed to cos square and cos. Use pythagorean identities to solve
Date Posted:
4 years ago
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