Question

calcule o valor de casa expressão

Answer 1

$a. \\ y = \frac{ \cos(90) - \cos(180) }{ \cos(60) \times \cos(0) + \cos(90) } \\ \\ y = \frac{0 - ( - 1)}{ \frac{1}{2} \times 1 + 0 } \\ \\ y = \frac{1}{ \frac{1}{2} } \\ \\ y = 1 \times \frac{2}{1} \\ \\ y = 2$
$b. \\ x = \cos( \frac{\pi}{4} ) \times \cos( \frac{\pi}{2} ) + \cos(\pi) \times \cos( \frac{\pi}{6} ) \\ \\ x = \cos( \frac{180}{4} ) \times \cos( \frac{180}{2} ) + \cos(180) \times \cos( \frac{180}{6} ) \\ \\ x = \cos(45) \times \cos(90) + \cos(180) \times \cos(30) \\ \\ x = \frac{ \sqrt{2} }{2} \times 0 \: + ( - 1) \times \frac{ \sqrt{3} }{2} \\ \\ x = 0 + ( - 1) \times ( \frac{ \sqrt{3} }{2} ) \\ \\ x = - \frac{ \sqrt{3} }{2}$

Espero ter ajudado ;)