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secondary 4 | A Maths
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Candice
Candice

secondary 4 chevron_right A Maths chevron_right Singapore

Hi urgently need an answer for this question! Thank you very much

Date Posted: 4 years ago
Views: 241
Candice
Candice
4 years ago
Thank u :)
J
J
4 years ago
sin²2θ(cot²θ - tan²θ)

= (2sinθcosθ)² (cos²θ/sin²θ - sin²θ/cos²θ)

(Remember cotθ = cosθ/sinθ and tanθ = sinθ/cos, so the above are just squared)

= 4sin²θcos²θ ( (cos⁴θ - sin⁴θ)/(sin²θcos²θ) )

= 4(cos⁴θ - sin⁴θ)

= 4(cos²θ + sin²θ)(cos²θ - sin²θ)

(Property used here is a² - b² = (a+b)(a - b) )

= 4(1)(cos2θ)
= 4cos2θ

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Eric Nicholas K
Eric Nicholas K's answer
5997 answers (Tutor Details)
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Good evening Candice!!! Here are my workings for this question.
Candice
Candice
4 years ago
Thank you
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Jiayang
Jiayang's answer
1883 answers (Tutor Details)