Which of these is equivalent?

Geometry Level 1

4 cos 2 θ 2 sin 2 θ 2 cos 2 θ \large \dfrac { { 4\cos ^{ 2 }{ \frac { \theta }{ 2 } } \sin ^{ 2 }{ \frac { \theta }{ 2 } } } }{ \cos ^{ 2 }{ \theta } }

Simplify the trigonometric expression above.

cot 2 θ \cot^{2} {\theta} tan 3 θ \tan^{3} {\theta} 1 sin 2 θ 1-\sin^{2} {\theta} tan 2 θ \tan^{2} {\theta} csc 2 θ \csc^{2} {\theta} sin 2 θ \sin^{2} {\theta}

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2 solutions

4 cos 2 θ 2 sin 2 θ 2 cos 2 θ = ( 2 cos θ 2 sin θ 2 ) 2 cos 2 θ = sin 2 θ cos 2 θ = tan 2 θ \large \displaystyle \begin{aligned} \frac{4 \cos^2 \frac{\theta}{2} \sin^2 \frac{\theta}{2}}{\cos^2 \theta} &= \frac{\left(2 \cos \frac{\theta}{2} \sin \frac{\theta}{2} \right)^2}{\cos^2 \theta}\\ \large \displaystyle &= \frac{\sin^2 \theta}{\cos^2 \theta}\\ \large \displaystyle &= \tan^2 \theta \end{aligned}

Formula Used: sin 2 θ = 2 × sin θ × cos θ . \large \displaystyle \text{Formula Used: } \sin 2 \theta = 2 \times \sin \theta \times \cos \theta.

Nice solution. Keep it up!

Sandeep Bhardwaj - 5 years ago

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Thank You! ¨ \Large \ddot\smile

Samara Simha Reddy - 5 years ago
Icaro Buscarini
May 18, 2016

@Icaro Buscarini

Nice problem. :)

The solution can be improved by using the latex at the place of the lonely image. ;) You can find the latex guide here . Thanks!

Sandeep Bhardwaj - 5 years ago

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Thank you! ;)

Icaro Buscarini - 5 years ago

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