Question

.已知函數(shù)y=x³＋ax²－a的導(dǎo)數(shù)為0的x值也使y值為0，則常數(shù)a的值為

A.0                                                                 B.±3

C.0或±3                                                        D.非以上答案

Answer 1

C

解析:

本題考查常見(jiàn)函數(shù)的導(dǎo)數(shù)及其應(yīng)用.

y′=3x²＋2ax.

令y′=3x²＋2ax=0,得x=0或x=－a.

當(dāng)x=0時(shí)，得－a=0,∴a=0；

當(dāng)x=－a時(shí)，－a³＋a³－a=0,得a=±3.