Question

Determine o valor de A na expressão:
$A = Sen\frac{x}{2} - 4 Cos (2x)$ e $X = \pi$

Answer 1

$\displaystyle \text A = \text{Sen}(\frac{\text x}{2}) - 4.\text{Cos}(2\text x ) \ \ , \text e \ \text x = \pi$

substituindo $\text x = \pi$, lembrando que na trigonometria $\pi = 180^{\circ}$

$\displaystyle \text A = \text{Sen}(\frac{\pi}{2}) - 4.\text{Cos}(2\pi )$

$\displaystyle \text A = \text{Sen}(90^{\circ}) - 4.\text{Cos}(360^{\circ} )$

$\displaystyle \text A = 1 - 4.1$

$\huge\boxed{\displaystyle \text A = -3}$

Letra C