A 9 B 6 C 8 D 4 E 12

A <img width="80" height="40" src="https://www.beizhujiaoyu.com/uploads/202208/20211222221923_0059.jpg" title="" align="" alt="" /> B <img width="110" height="29" src="https://www.beizhujiaoyu.com/uploads/202208/20211222221923_1789.jpg" title="" align="" alt="" /> C <img src="https://www.beizhujiaoyu.com/uploads/202208/164249110015981.jpg" alt="" width="60" height="45" title="" align="" /> D e^-x+xe^-x E x+lnx+C

A <img width="50" height="37" src="https://www.beizhujiaoyu.com/uploads/202208/20211222221927_2559.jpg" title="" align="" alt="" /> B <img width="50" height="38" src="https://www.beizhujiaoyu.com/uploads/202208/20211222221927_4122.jpg" title="" align="" alt="" /> C <img width="50" height="39" src="https://www.beizhujiaoyu.com/uploads/202208/20211222221929_3654.jpg" title="" align="" alt="" /> D 0 E <img width="50" height="39" src="https://www.beizhujiaoyu.com/uploads/202208/20211222221929_5373.jpg" title="" align="" alt="" />

A <img width="220" height="37" src="https://www.beizhujiaoyu.com/uploads/202208/20211222221931_4903.jpg" title="" align="" alt="" /> B <img width="160" height="32" src="https://www.beizhujiaoyu.com/uploads/202208/20211222221931_6633.jpg" title="" align="" alt="" /> C <img width="220" height="38" src="https://www.beizhujiaoyu.com/uploads/202208/20211222221933_6153.jpg" title="" align="" alt="" /> D <img width="160" height="31" src="https://www.beizhujiaoyu.com/uploads/202208/20211222221933_7715.jpg" title="" align="" alt="" /> E <img width="220" height="31" src="https://www.beizhujiaoyu.com/uploads/202208/20211222221935_7247.jpg" title="" align="" alt="" />

A <img width="36" height="30" src="https://www.beizhujiaoyu.com/uploads/202208/20211222221937_8341.jpg" title="" align="" alt="" /> B ln 4 C ln 5 D ln 2 E <img width="40" height="24" src="https://www.beizhujiaoyu.com/uploads/202208/20211222221937_9904.jpg" title="" align="" alt="" />

A <img width="16" height="45" src="https://www.beizhujiaoyu.com/uploads/202208/20211222221940_1309.gif" title="" align="" alt="" /> B ∞ C <img width="16" height="35" src="https://www.beizhujiaoyu.com/uploads/202208/20211222221942_1778.jpg" title="" align="" alt="" /> D 0 E <img width="16" height="31" src="https://www.beizhujiaoyu.com/uploads/202208/20211222221942_3789.jpg" title="" align="" alt="" />

A 4 B -2 C 2或-2 D 2 E 4或-4

A K<J<I B I<K<J C K<I<J D I<J<K E J<I<K

A <img width="93" height="46" src="https://www.beizhujiaoyu.com/uploads/202208/20211222221946_4434.jpg" /> B <img width="80" height="46" src="https://www.beizhujiaoyu.com/uploads/202208/20211222221946_6309.jpg" /> C <img width="79" height="46" src="https://www.beizhujiaoyu.com/uploads/202208/20211222221948_5840.jpg" /> D <img width="63" height="46" src="https://www.beizhujiaoyu.com/uploads/202208/20211222221949_0841.jpg" /> E <img width="94" height="46" src="https://www.beizhujiaoyu.com/uploads/202208/20211222221950_7716.jpg" />

A 0 B f(x，y) C 2xf(x，y) D 2x²f(x，y) E 2yf(x，y)