Question

Вычислите:
а)
$cos15pi$
б)
$sin frac{25pi}{2}$
​

Answer 1

а)

$cos(15pi) = cos( pi + 2 times 7pi) = cos(pi) = - 1$

б)

$sin( frac{25pi}{2} ) = sin( frac{pi}{2} + 2 times 6pi ) = sin( frac{pi}{2} ) = 1$