填空题:设z=xy，则dz= .

A 充分条件 B 必要条件 C 充要条件 D 以上都不对

A e2 B e-2 C 1 D 0

A a=-9，b=14 B a=1,b=-6 C a=-2，b=0 D a=-2，b=-5

A 有一个拐点 B 有两个拐点 C 有三个拐点 D 无拐点

A 3x2+C B <img src="https://www.beizhujiaoyu.com/uploads/202208/20190828104626_0247.png" width="56" height="40" /> C x3+C D <img src="https://www.beizhujiaoyu.com/uploads/202208/20190828104633_4466.png" width="52" height="33" />

A 0或1 B 0或-1 C 0或2 D 1或-1

A <img src="https://www.beizhujiaoyu.com/uploads/202208/20190828104649_6966.png" width="131" height="40" /> B <img src="https://www.beizhujiaoyu.com/uploads/202208/20190828104654_5560.png" width="131" height="40" /> C <img src="https://www.beizhujiaoyu.com/uploads/202208/20190828104658_3997.png" width="261" height="42" /> D <img src="https://www.beizhujiaoyu.com/uploads/202208/20190828104702_9466.png" width="262" height="40" />

A 取得极大值 B 取得极小值 C 无极值 D 无法判定

A 收敛 B 发散 C 收敛且和为零 D 可能收敛也可能发散

A Ax B Ax+B C Ax2+Bx D Ax2+Bx+C