Ответ:
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=sin(75-15)=sin 60=√3/2
f (x)=2/x -- x^2
D (f)=(0;+~~)
f '(x)=2/x^2 -- 2x
2/x^2 -- 2x=0
2-2x^3/x^2 =0
2-2x^3=0
x=1
____+____¤_______---____
1
x (max)=1