A) y(-1/2)=(-1/2)^2=1/4
б) y(3)=3^2=9
15х(-3(19-18))+3х=х+90+2х
15х(-57+54х)+3х=х+90+2х
-855х+660х^+3х=х+90+2х
660х^-855х+3х-х-2х=90
660х^-855х=90
15х(44х-57)=90
1)15х=90 2)44х-57=90
х=6 44х=90-57
44х=33
х=3/4
2sin3x=k3
sin3x=k3/2
3x=(-1)^k p/3+pn
x=(-1)^k p/9+pn/3
5sin2x-2sinx=0
10sinxcosx-2sinx=0
2sinx(5cosx-1)=0
2sinx=0 sinx=0 x=pn
5cosx-1=0 cosx=1/5 x=arccos(1/5)+2pk
1+cosx-cosx/2=0
2cos^2 x/2 -cosx/2=0
cosx/2(2cosx/2-1)=0
cosx/2=0 x/2=p/2+pn x=p+2pn
2cosx/2=1 cosx/2=1/2 x/2=p/3+2pn x=2p/3+4pn