Verified answer

Ответ:

Объяснение:

F*sin(a)+N=mg

F*cos(a)-kN=0

N=mg-F*sin(a)=F*cos(a)/k

mg=F*(cos(a)/k+sin(a))

F=mg/(cos(a)/k+sin(a))

F`=-mg/(cos(a)/k+sin(a))^2*(-sin(a)/k+cos(a)=0

tg(a)=k

sin(a)=k/√(1+k²)

cos(a)=1/√(1+k²)

F=mg/(cos(a)/k+sin(a))=mg/(1/√(1+k²):k+k/√(1+k²))=

=mg/(1/k*1/√(1+k²)+1/k*k²/√(1+k²)) = k*mg/√(1+k²)