<span>16-y^2 = (4-y)*(4+y)
</span><span>1/8km^3 +kn^3 = k*(1/2m+n)*(1/4m^2-1/2mn+n^2)</span>
Q= -2/5 = -0, 4 это и есть знаменатель геом. прогрессии
Корень из 209=14,4568322948
Ответ::::::::..................
Α - угол четвёртой четверти, значит Sinα < 0
![Sin \alpha =- \sqrt{1-Cos ^{2} \alpha } =- \sqrt{1-( \frac{1}{3}) ^{2} }=- \sqrt{1- \frac{1}{9} } =- \sqrt{ \frac{8}{9} } =- \frac{2 \sqrt{2} }{3}\\\\\\Sin2 \alpha =2Sin \alpha Cos \alpha =2*(- \frac{2 \sqrt{2} }{3} )* \frac{1}{3} =- \frac{4 \sqrt{2} }{9}\\\\\\ \frac{Sin2 \alpha }{ \sqrt{2} }=- \frac{4 \sqrt{2} }{9} * \frac{1}{ \sqrt{2} }=- \frac{4}{9}](https://tex.z-dn.net/?f=Sin+%5Calpha+%3D-+%5Csqrt%7B1-Cos+%5E%7B2%7D++%5Calpha+%7D+%3D-+%5Csqrt%7B1-%28+%5Cfrac%7B1%7D%7B3%7D%29+%5E%7B2%7D++%7D%3D-+%5Csqrt%7B1-+%5Cfrac%7B1%7D%7B9%7D+%7D+%3D-+%5Csqrt%7B+%5Cfrac%7B8%7D%7B9%7D+%7D+%3D-+%5Cfrac%7B2+%5Csqrt%7B2%7D+%7D%7B3%7D%5C%5C%5C%5C%5C%5CSin2+%5Calpha+%3D2Sin+%5Calpha+Cos+%5Calpha+%3D2%2A%28-+%5Cfrac%7B2+%5Csqrt%7B2%7D+%7D%7B3%7D+%29%2A+%5Cfrac%7B1%7D%7B3%7D+%3D-+%5Cfrac%7B4+%5Csqrt%7B2%7D+%7D%7B9%7D%5C%5C%5C%5C%5C%5C+%5Cfrac%7BSin2+%5Calpha+%7D%7B+%5Csqrt%7B2%7D+%7D%3D-+%5Cfrac%7B4+%5Csqrt%7B2%7D+%7D%7B9%7D+%2A+%5Cfrac%7B1%7D%7B+%5Csqrt%7B2%7D+%7D%3D-+%5Cfrac%7B4%7D%7B9%7D++++++)