设<img src="/lqwvjeImg/e2/e2eda903de82f5ed40d618479bd25293.png"style="width:37px;height:21px;">是正定矩阵,则以下矩阵中,一定是正定矩阵为(其中<img src="/lqwvjeImg/9a/9a6ed446b95af57883486661e8f2c173.png"style="width:38px;height:22px;">为任意常数) ( )<br>·<img src="/lqwvjeImg/19/195af5a44af364adba5aa27b19f90a48.png"style="width:52px;height:21px;">;<br>·<img src="/lqwvjeImg/2f/2f707af66f5affb6f25aebf353fca1a8.png"style="width:54px;height:19px;">;<br>·<img src="/lqwvjeImg/78/787ae94e437272bd4548b94e3dd48ef2.png"style="width:38px;height:19px;">;<br>·<img src="/lqwvjeImg/af/af9569bb006712dd241cd08bb1ea9f59.png"style="width:78px;height:23px;">。