Sin(49*pi/12)*(sin^4(59*pi/24) - sin^4(49*pi/24)). Как найти значение этого выражения?

Решите задачу:

$=sin(4 \pi + \frac{\pi}{12})*(sin^4(2\pi+\frac{11 \pi}{24}) -sin^4(2\pi +\frac{\pi}{24})) = \\ sin(\frac{\pi}{12})*(sin^4(\frac{11 \pi}{24}) -sin^4(\frac{\pi}{24})) = \\ sin(\frac{\pi}{12})*(sin^4( \frac{\pi}{2} - \frac{\pi}{24}) -sin^4(\frac{\pi}{24})) = \\ sin(\frac{\pi}{12})*(cos^4(\frac{\pi}{24}) -sin^4(\frac{\pi}{24})) = \\ sin(\frac{\pi}{12})*(cos^2(\frac{\pi}{24}) -sin^2(\frac{\pi}{24}))*(cos^2(\frac{\pi}{24}) +sin^2(\frac{\pi}{24})) = \\ sin(\frac{\pi}{12}) *cos(2*\frac{\pi}{24})*1=$
$=sin(\frac{\pi}{12}) *cos(\frac{\pi}{12}) = \frac{2*sin(\frac{\pi}{12}) *cos(\frac{\pi}{12})}{2} = \frac{sin(\frac{\pi}{6})}{2} = \frac{\frac{1}{2} }{2} =\frac{1}{4} =0,25$