BluePink BluePink
XHost 		Oferim servicii de instalare, configurare si monitorizare servere linux (router, firewall, dns, web, email, baze de date, aplicatii, server de backup, domain controller, share de retea) de la 50 eur / instalare. Pentru detalii accesati site-ul BluePink.
Matematica
O  n  l  i  n  e
|| Teoreme ::: Formule ::: Graficele unor functii uzuale ||
Trigonometrie
cos2x + sin2x = 1
sin(x+y)=sinx cosy + cosx siny
sin(x-y)=sinx cosy - cosx siny
cos(x+y)=cosx cosy - sinx siny
cos(x-y)=cosx cosy + sinx siny
tg(x + y)=(tgx + tgy)/(1 - tgx tgy)
tg(x - y)=(tgx - tgy)/(1 + tgx tgy)
sinx cosy=1/2 *(sin(x + y) + sin(x - y))
cosx cosy=1/2 *(cos(x + y) + cos(x - y))
sinx siny=1/2 *(cos(x - y) - cos(x + y))
sin2x=2sinx cosx
cos2x= 1 - sin2x
sin3x=3sinx - 4sin3x
cos3x=4cos3x - 3cosx
sinx + siny=2sin[(x+y)/2] cos[(x-y)/2]
sinx - siny=2sin[(x-y)/2] cos[(x+y)/2]
cosx + cosy=2cos[(x+y)/2] cos[(x-y)/2]
cosx - cosy=2sin[(x+y)/2] cos[(y-x)/2]
1 - cosx=2sin2(x/2)
1 + cosx=2cos2(x/2)
tg(x/2)=tsinx= 2t/(1+t2)
tg(x/2)=tcosx=(1-t2)/(1+t2)