填空题:设曲线y=k(x²-3)²(k>0)，若曲线在拐点的法线通过原点，则k=____.

A a=2，b=1． B a=2，b=-1． C a=1，b=1． D a=1，b=-1．

A 0． B 1． C 2． D 3．

A <img src="https://www.beizhujiaoyu.com/uploads/202208/165201254234061.png" width="58" height="18" />  B <img src="https://www.beizhujiaoyu.com/uploads/202208/165201254762851.png" width="58" height="18" />  C x =2． D x=3．

A a=2，b=-2． B a=-2，b=2． C a=-2，b=-2． D a=2，b=2．

A <img src="https://www.beizhujiaoyu.com/uploads/202208/165172606660101.png" width="63" height="28" /> B <img src="https://www.beizhujiaoyu.com/uploads/202208/1651726072941.png" width="62" height="28" /> C <img src="https://www.beizhujiaoyu.com/uploads/202208/165172607684971.png" width="98" height="32" /> D <img src="https://www.beizhujiaoyu.com/uploads/202208/165172608065231.png" width="97" height="33" />

A <img src="https://www.beizhujiaoyu.com/uploads/202208/165181333751591.png" width="160" height="35" /> B <img src="https://www.beizhujiaoyu.com/uploads/202208/16518133408821.png" width="160" height="34" /> C <img src="https://www.beizhujiaoyu.com/uploads/202208/16518133495461.png" width="155" height="34" /> D <img src="https://www.beizhujiaoyu.com/uploads/202208/165181335323921.png" width="246" height="34" />

A I₁<I₂<I₃． B I₂<I₃<I₁． C I₃<I₂<I₁． D I₁<I₃<I₂．

A dx-dy． B dx+dy． C -2dx-dy． D 2dx-dy．

A 若A～B，则A^m～B^m． B 若A～B，则λE-A～λE-B． C 若A～B且A，B可逆，则A^-1+A*～B^-1+B*． D 若A～B，则A+A^T～B+B^T．