А^2+а^2=5^2
2а^2=25
S=a^2=25/2=12.5
2 8/9 : 1/90 = 26/9 : 1/90 = 26/9 * 90 = 26 * 90 / 9 = 26 * 10 = 260.
Vпир=1/3×Sосн.×h
Sосн.=10×4=40см.кв
Vпир.=1/3×40×8=320/3==106,7см.куб
Номер 182 : а) f(X)= 3x^2-1/X+1= (3x^2-1)'(x+1)-(3x^2-1)(X+1)' / (X+1)^2 = 6x^2+6x-3x^2+1 / (X+1)^2= 3x^2+6x +1/ (X+1)^2