1.求函数 y=ln(x^2+3x+2)的n阶导数dny/dx^n.明天上午必须得出答案!2.讨论函数f(x)=x^4-2x^3 +1的凹凸性与拐点.
问题描述：
1.求函数 y=ln(x^2+3x+2)的n阶导数dny/dx^n.明天上午必须得出答案!
2.讨论函数f(x)=x^4-2x^3 +1的凹凸性与拐点.
答
y = ln(x²+3x+2)dy/dx = (2x+3)/(x²+3x+2) = (2x+3)/[(x+2)(x+1)] = (x+2)^(-1) + (x+1)^(-1),n = 0d²y/dx² = (-1)(1!)(x+2)^(-2) + (-1)(1!)(x+1)^(-2),n = 1d³y/dx³ = (-1)²(2...