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+)
36x^2-25=0
(6x-5)(6x+5)=0
6x-5=0 U 6x+5=0
x=5/6 U x=-5/6
Ответ:x1=-5/6; x2=5/6
А²-4а+9а²-а-2=10а²-5а-2
р(-3)=10*(-3)²-5*(-3)-2=10*9+15-2=90+13=103
3(a+2)+b(a+2)=(a+2)(3+b); 4f(5m-3n)-5k(5m-3n)=(5m-3n)(4f-5k); 5m(a-3b)+(a-3b)=(a-3b)(5m+1); 5m(a-3b)-a+3b=5m(a-3b)-(a-3b)=(a-3b)(5m-1).
X²-4ax+4=0
D<0
D=(-4a)²-4*1*4=16a²-16
16a²-16<0 |:16
a²-1<0
(a-1)(a+1)<0
+ - +
__________-1__________1__________
a∈(-1;1)