Kosinus

$\displaystyle \cos^2 x$	$\displaystyle =$	$\displaystyle \frac{1}{2}\ \Big(1 + \cos (2x) \Big)$
$\displaystyle \cos^3 x$	$\displaystyle =$	$\displaystyle \frac{1}{4}\ \Big(3 \cos x + \cos (3x) \Big)$
$\displaystyle \cos^4 x$	$\displaystyle =$	$\displaystyle \frac{1}{8}\ \Big(3 + 4 \cos (2x) + \cos (4x) \Big)$
$\displaystyle \cos^5 x$	$\displaystyle =$	$\displaystyle \frac{1}{16}\ \Big(10 \cos x + 5 \cos (3x) + \cos (5x) \Big)$
$\displaystyle \cos^6 x$	$\displaystyle =$	$\displaystyle \frac{1}{32}\ \Big(10 + 15 \cos (2x) + 6 \cos (4x) + \cos (6x) \Big)$