Y=cosx
y'(x) = (cosx)' = -sinx
1) (х-4)/(х^0,5+2)+2=(х^0,5-2)(х^0,5+2)/((х^0,5+)+2=х^0,5-2+2=х^0,5
2) 1/2х-х*1/2=0
(1-х^2)/2х=0
1-х^2=0
х^2=1
х1=1
х2=-1
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Cos75=cos(90-15)=-sin15
sin345=sin(360-15)=sin15
-sin15*sin15=-0.25
sin105=sin(180-75)=cos75
sin295=sin(360-75)=cos75
cos15*cos15=0.25
9х^2 + 7х + 13 = 0
а = 9; b = 7; с = 13
D = b^2 - 4 * а * с
D = 7^2 - 4 * 9 * с = - 419
Ответ : D = - 419