1) y' = 8x +6x²
2) y = 4x³ - x⁴
y' = 12x² - 4x ³
3)y'=( (3x² -3)(1 -2x) - (x³ -3x)*(-2))/(1 -2x)² =
=(3x² -6x³ -3 + 6x +2x³ -6x)/(1 -2x)²= (-4x³+3x² -3)/(1 -2x)²
4) b₅ = b₁q⁴
1/81 = b₁ *1/81
b₁ = 1
S= b₁/(1 -q) = 1/(1 -1/3) = 3/2 = 1,5
5) lim(x³ +x -5) = 3³ +3 -5 = 25
x→3