x^3-3X^2-4=0这个方程的实数解是x=(3+2√2)^(1/3)+(3-2√2)^(1/3)+1x约等于3.355301398x^3-3X^2-4对x求导(x^3 - 3x^2 - 4)' = 3x^2 - 6x导数等于零时3x^2 - 6x = 0 => x^2 - 2x = 0 => x(x - 2) = 0x1 = 0; x2 = 2x ...