0\\\\\\Cos\frac{\pi }{8} >0\\\\\frac{Sin\frac{6\pi }{7}*Cos\frac{\pi }{8}}{|Sin\frac{6\pi }{7}*Cos\frac{\pi }{8}|} =1" alt="Sin\frac{6\pi }{7}>0\\\\\\Cos\frac{\pi }{8} >0\\\\\frac{Sin\frac{6\pi }{7}*Cos\frac{\pi }{8}}{|Sin\frac{6\pi }{7}*Cos\frac{\pi }{8}|} =1" align="absmiddle" class="latex-formula">