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Fatiha
Fatiha
Date Posted: 4 years ago
Views: 751
J
J
4 years ago
1 - cot2θ tanθ

= (1/tanθ - cot2θ) (tanθ)

= (cosθ/sinθ - cos2θ/sin2θ) (tanθ)

= (cosθ/sinθ - (cos²θ - sin²θ)/(2sinθcosθ) ) (tanθ)

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

= ((cos²θ+sin²θ)/2sinθcosθ) (tanθ)

= (1/sin2θ) (tanθ)

= cosec2θ tanθ

(Shown)
J
J
4 years ago
Alternatively,


1 - cot2θtanθ

= 1 - (1/tan2θ)(tanθ)

= 1 - ((1-tan²θ)/(2tanθ)) (tanθ)

= 1 - (1-tan²θ)/2

= ½(1 + tan²θ)

= ½sec²θ

= (1/2cosθ)(1/cosθ)

= (1/2cosθ)(1/sinθ)(sinθ)(1/cosθ)

= (1/2sinθcosθ)(sinθ/cosθ)

= (1/sin2θ) tanθ

= cosec2θ tanθ

(Shown)

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Lau See Kei
Lau See Kei's answer
9 answers (Tutor Details)
1st
sometimes if ur stuck, try solving both sides halfway like what I did to get a better idea of what to do next