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# proving trigonometry

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how to prove sin(18$$^\circ$$) =  $$\cos (4 \cdot 18^{\circ})$$ using right triangle or unit circle

Feb 5, 2022

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You can use exponential notation.

Feb 5, 2022
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ok, let me try.

Dennis070sinneD  Feb 5, 2022
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Draw a right angle tiangle with one angle of 18degrees.  Work out what the other anglw will have to be.

Call the hypotenuse h and the other two sides x and y.

Now use the trianlge to prove, or at least convince youself and anyone looking over your shoulder, that is is true :)

Feb 5, 2022