Question

Arătați că dacă E(x) =cos (pi/2-x)+sin(pi-x), atunci E(pi/6).Urgentttt!!!! ​

Answer 1

 

$\displaystyle\bf\\E(x) =cos\Big(\frac{\pi}{2}-x\Big)+sin\Big(pi-x\Big)\\\\E(x) =sin\,x+sin\,x\\\\\boxed{\bf~E(x) =2sin\,x}\\\\\\E\Big(\frac{\pi}{6}\Big)=2sin\Big(\frac{\pi}{6}\Big)~~~unde~\frac{\pi}{6}=30^o\\\\E\Big(\frac{\pi}{6}\Big)=2\times\frac{1}{2}\\\\ \boxed{\bf~E\Big(\frac{\pi}{6}\Big)=1}$