Ответы и объяснения

  • IOriOnI
  • почетный грамотей
2012-05-16T12:58:36+00:00

cos(p/4+x)-cos(p/4-x)=1

cos(p/4+x) = cospi/4*cosx - sinx*sinpi/4 = 2/2(cosx-sinx)

cos(p/4-x) = cospi/4*cosx + sinx*sinpi/4 =2/2(cosx+sinx)

cos(p/4+x)-cos(p/4-x) = 2/2(cosx-sinx) - (2/2(cosx+sinx)) = 2/2(cosx-sinx-cosx-sinx) = -√2/2 * sinx = -√2sinx

cos(p/4+x)-cos(p/4-x)=1   =>

-√2sinx =1

sinx= - 2/2

x=((-1)^(k+1))  *pi/4+pi*k