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Rom4ik [11]
1 year ago
7

Given that cos(theta) = -2 radical 5/5, and is in Quadrant II, what is cos(2theta)?

Mathematics
1 answer:
gtnhenbr [62]1 year ago
5 0

cos \theta =  \frac{ - 2 \sqrt{5} }{5}

cos 2\theta = 2cos {}^{2}  \theta - 1 \\ cos2 \theta = 2( \frac{ - 2 \sqrt{5} }{5} ) {}^{2}  - 1 \\ cos2 \theta = 2( \frac{20}{ \\ 25} ) - 1 \\ cos2 \theta =  \frac{40 - 25}{25}  =  \frac{15}{25}  =  \frac{3}{5}

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Answer:

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Step-by-step explanation:

Pythagorean theorem is a^2+b^2=c^2.

Plug the given values in to get 61^2+b^2=82^2

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The square root of 3,003, rounded to a reasonable value, is 54.8.

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So the price of a ticket is $5, and the cost to put on the show is $100.
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3 years ago
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