Question

Urgent !

x aparține ( 3pi / 2 ; 2pi )
sin x = -1 / 2
cos x = ?​

Answer 1

Răspuns:

$x$∈$(\frac{3\pi }{2},2\pi )$

$sinx=-\frac{1}{2}$ $=> x$∈$\frac{11\pi }{6}+2k\pi$, unde k este un numar intreg

$=> cos(\frac{11\pi }{6})=\frac{\sqrt{3} }{2}$

$cos(x)=\frac{\sqrt{3} }{2}$