f(x)=0 при x<af(x)=0 при x>bf(x)=c при a<x<bintegral [-беск;+беск] f(x)*dx =integral [a;b] c*dx = c*(b-a)=1c=1/(b-a)f(x)=1/(b-a) при a<x<bMX==integral [-беск;+беск] f(x)*x*dx ==1/(b-a)* integral [a;b] x*dx = =1/(b-a)* x^2/2 [a;b] ==1/(b-a)* ( b^2/2 - a^2/2) ==(b+a)/2 = 3MX^2==integral [-беск;+беск] f(x)*x^2*dx ==1/(b-a)* integral [a;b] x^2*dx = =1/(b-a)* x^3/3 [a;b] ==1/(b-a)* ( b^3/3 - a^3/3) ==(b^2+ab+a^2)/3DX==MX^2 - (MX)^2==(b^2+ab+a^2)/3 - (b+a)^2/4 = = (4b^2+4ab+4a^2-3b^2-6ab-3a^2)/12 = = (b^2-2ab+a^2)/12 = = (b-a)^2/12 = = 4/3***************************(b+a)/2 = 3(b-a)^2/12 = 4/3****************b+a = 6(b-a)^2 = 16****************b+a = 6b-a= 4****************b=5;a=1f(x)=0 при x<1f(x)=0 при x>5f(x)=1/4 при 1<x<5F(x)=integral [-беск;x] f(t)*dtF(x)=0 при x<1F(x)=(x-1)/4 при 1<x<5F(x)=1 при x>5P(x є [2;5]) = F(5) - F(2) = 1 - (2-1)/4 = 3/4