1) x = 5
2) x = 1/3
3) x = 125
4) x = 8
5) x принадлежит промежутку (2; +бесконечности)
6) x принадлежит промежутку (0; 1)
-24<2a<20
60>-5a>-50
12>-a>-10
-7<a+5<15
-4<8-a<-2
-1/12<1/a<-1/10
-1/4<3/a<3/10
-23<2a+1<21
41>5-3a>-25
X=y, поставляем и получаем x=4x-12, x=4, у=4
![sin( \frac{3 \pi }{2}+arccos \frac{1}{3} )= \\ = sin(\frac{3 \pi }{2})*cos(arccos \frac{1}{3})+cos(\frac{3 \pi }{2})*sin(arccos \frac{1}{3})= \\ =- \frac{1}{3} \\ sin(2arccos \frac{3}{5} )=2*sin(arccos \frac{3}{5})*cos(arccos \frac{3}{5})= \\ =2* \sqrt{1- \frac{9}{25} } * \frac{3}{5} = \frac{6}{5} * \frac{4}{5} = \frac{24}{25} =0.96](https://tex.z-dn.net/?f=sin%28+%5Cfrac%7B3+%5Cpi+%7D%7B2%7D%2Barccos+%5Cfrac%7B1%7D%7B3%7D+%29%3D+%5C%5C+%3D+sin%28%5Cfrac%7B3+%5Cpi+%7D%7B2%7D%29%2Acos%28arccos+%5Cfrac%7B1%7D%7B3%7D%29%2Bcos%28%5Cfrac%7B3+%5Cpi+%7D%7B2%7D%29%2Asin%28arccos+%5Cfrac%7B1%7D%7B3%7D%29%3D+%5C%5C+%0A%3D-+%5Cfrac%7B1%7D%7B3%7D++%5C%5C+%0Asin%282arccos+%5Cfrac%7B3%7D%7B5%7D+%29%3D2%2Asin%28arccos+%5Cfrac%7B3%7D%7B5%7D%29%2Acos%28arccos+%5Cfrac%7B3%7D%7B5%7D%29%3D+%5C%5C+%0A%3D2%2A+%5Csqrt%7B1-+%5Cfrac%7B9%7D%7B25%7D+%7D+%2A+%5Cfrac%7B3%7D%7B5%7D+%3D+%5Cfrac%7B6%7D%7B5%7D+%2A+%5Cfrac%7B4%7D%7B5%7D+%3D+%5Cfrac%7B24%7D%7B25%7D+%3D0.96)
cos(arccos(a))=a
sin(arccos(a))=√(1-a²)
cos(arcsin(a))=√(1-a²)
sin(2a)=2sin(a)cos(a)
sin(a+b)=sin(a)*cos(b)+cos(a)sin(b).