PlanetMath: cosine at multiples of straight angle

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cosine at multiples of straight angle

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Everybody remembers the cosine values

$\displaystyle \cos 0 = 1,\quad \cos(\pm\pi) = -1,\quad \cos(\pm2\pi) = 1,\quad \cos(\pm3\pi) = -1,\,\,...$

The thing can be concisely expressed as the formula

$\displaystyle \cos{n\pi} = (-1)^n$

for each integer

. The values of sine at the same angles are simply 0.

"cosine at multiples of straight angle" is owned by pahio.

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Keywords:

straight angle

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Cross-references: angles, sine, integer, cosine
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This is version 3 of cosine at multiples of straight angle, born on 2006-03-12, modified 2007-01-19.
Object id is 7716, canonical name is CosineAtMultiplesOfStraightAngle.
Accessed 879 times total.

Classification:

26A09 (Real functions :: Functions of one variable :: Elementary functions)

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