CMR: sin(pi/24)* sin(5pi/24)* sin(7pi/24)* sin(11pi/24)=1/16

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1. $VT=\Big(\sin\dfrac{\pi}{24}.\sin\dfrac{11\pi}{24}\Big).\Big(\sin\dfrac{5\pi}{24}.\sin\dfrac{7\pi}{24}\Big)$

   $=-\dfrac{1}{2}\Big(\cos\dfrac{\pi}{2}-\cos\dfrac{5\pi}{12}\Big).\dfrac{-1}{2}.\Big(\cos\dfrac{\pi}{2}-\cos\dfrac{\pi}{12}\Big)$

   $=\dfrac{1}{4}.(-1).(-1).\cos\dfrac{5\pi}{12}.\cos\dfrac{\pi}{12}$ 

   $=\dfrac{1}{4}.\dfrac{1}{2}\Big(\cos\dfrac{\pi}{2}+\cos\dfrac{\pi}{3}\Big)$

   $=\dfrac{1}{4}.\dfrac{1}{2}.\dfrac{1}{2}$

   $=\dfrac{1}{16}$

   $=VP$

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