Răspunsuri

2014-09-14T15:04:04+03:00
Sin(x)+sin(3x)+sin(5x)=sin(x)+sin(5x)+sin(3x)= 2sin(3x)cos(-2x)+sin(3x)= (sin(3x))*(2cos(2x)+1), unde am folosit sin(x)+sin(y)=2sin((x+y)/2)cos((x-y)/2) si cos(-x)=cos(x)