X+y>10
y>10-x
Гипотеза - Эти точки располагаются выше графика функции y=10-x
Y'=(3x+1)'*ctg(-x)+(3x+1)*(ctg(-x))'=3*ctg(-x)+(3x+1)*(
![\frac{-1}{ sin^{2}(x) } *(-1))](https://tex.z-dn.net/?f=+%5Cfrac%7B-1%7D%7B+sin%5E%7B2%7D%28x%29+%7D+%2A%28-1%29%29)
=-3*ctg(x)+
![\frac{1}{ sin^{2}(x) }](https://tex.z-dn.net/?f=+%5Cfrac%7B1%7D%7B+sin%5E%7B2%7D%28x%29+%7D)
=
![\frac{-3cos x*sin x+3x+1}{ sin^{2}(x) } = \frac{-3/2sin (2x)+3x+1}{ sin^{2}(x) }](https://tex.z-dn.net/?f=+%5Cfrac%7B-3cos+x%2Asin+x%2B3x%2B1%7D%7B+sin%5E%7B2%7D%28x%29+%7D+%3D+%5Cfrac%7B-3%2F2sin+%282x%29%2B3x%2B1%7D%7B+sin%5E%7B2%7D%28x%29+%7D+)
√2cosxcosπ/4+√2sinxsinπ/4-cosx=√3/2
√2*1/√2*cosx+√2*1/√2*sinx-cosx=√3/2
cosx+sinx-cosx=√3/2
sinx=√3/2
x=(-1)^n*π/3+πn,n∈Z