A、曲线<img src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/examination/imgUplod/1620627875095ec6ccdcb531c4b78800c0e7ec1b3dbc0image19.png"style="width:44px;height:24px;"/>在定义域内是凹的.
B、曲线<img src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/examination/imgUplod/162062787514024b3dd6152364f20b15e5e04c4530be9image20.png"style="width:53px;height:24px;"/>在定义域内是凸的.
C、曲线<img src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/examination/imgUplod/1620627875166a61cf3b6d18740ae94150ab0020f5030image21.png"style="width:42px;height:24px;"/>在定义域内是凹的.
D、曲线<img src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/examination/imgUplod/16206278751965dd660e7ee6f4c81bf41902a88de47ebimage22.png" style="width:42px;height:24px;">在<img src="https://s3.cn-north-1.amazonaws.com.cn/qingshuxuetang/examination/imgUplod/1620627932730_693a47e9245c481fa635b6e52d8b6a49.png">内是凹的.