下列说法中正确的是( )。<br>·若<img src="/lqwvjeImg/7d/7d6f234ed32627b5f7295a1b12c85778.png" >,<img src="/lqwvjeImg/f4/f42679c19ac495da8eeb89e366937728.png" >,且<img src="/lqwvjeImg/6d/6d15068e0474a7b7620ea7b33e9c157f.png" >,则<img src="/lqwvjeImg/5a/5a3dfee7509af180ab0ee8141775d155.png" >一定不存在。<br>·若<img src="/lqwvjeImg/90/90a43d3e8aa1da865bb8d661fa96a06e.png" >在点<img src="/lqwvjeImg/f6/f6cb793ea0aaa9e4e01324f5d94f780b.png" >处连续,则<img src="/lqwvjeImg/79/797f90d0ad12e76059379b0fd1ad4392.png" >。<br>·如果<img src="/lqwvjeImg/d5/d5c7e2532f7531545ab061f571ff5c5a.png" >,则点<img src="/lqwvjeImg/f6/f6cb793ea0aaa9e4e01324f5d94f780b.png" >必是函数<img src="/lqwvjeImg/d0/d0bce4ece4d7a8141933ffbbfff034ad.png" >的极值点。<br>·若<img src="/lqwvjeImg/84/8480245ba8a9b6283afcba80a40dc24f.png" >,<img src="/lqwvjeImg/dd/dde0c1d075172b7b74c59e4e76fe5cc1.png" >都是<img src="/lqwvjeImg/43/43ca41fc17b71bd30c46d3c7462ab2fe.png" >的原函数,则<img src="/lqwvjeImg/e4/e42e1be478f7a7a29a5867476e5ac8f3.png" >,其中<img src="/lqwvjeImg/a9/a951b4831dd8a891f06a7d6582739814.png" >为常数。