17. 写出下面两个的相关命题的逆命题、否命题、逆否命题,并判断它们的真假:
(1)命题:若
,则
.
逆命题:_______________________________________________________(
)
逆否命题:_____________________________________________________(
)
(2)命题:设
是实数,如果
,那么
有实数根.
否命题:_______________________________________________________(
)
逆否命题:_____________________________________________________(
)