>24
　sin(z) = sin(x+iy) = sin(x)cos(iy) + cos(x)sin(iy) = sin(x)cosh(y) +i*cos(x)sinh(y),
　cos(z) = cos(x+iy) = cos(x)cos(iy) - sin(x)sin(iy) = cos(x)cosh(y) -i*sin(x)sinh(y),
辺々割る。