第1896题：拐点
求曲线
y=x3+2x2y=x^3+2x^2y=x3+2x2−5x+10 -5x+10−5x+10
的拐点.
A. (−1,16)(-1,16)(−1,16)
B. (1,7) (1,7)(1,7)
C. (−23,132527)\Big ( -\dfrac{2}{3},13\dfrac{25}{27} \Big )(−32,132725)
D. (−12,1278)\Big ( -\dfrac{1}{2}, 12\dfrac{7}{8} \Big )(−21,1287)
