写出下列线性规划问题的对偶问题：minZ=2x18x2−4x3{x13x2−3x3≥30−x15x24x3=804x12x2−4x3≤50x1≤0,x2≥0,x3无限制
The reason why the four other climate pollutants can disappear in a matter of weeks is that______.
A. nearly 100 ozone-depleting chemicals have been phased out under the Montreal Protocol
B. they account for as much as 40 percent of current warming
C. more than 100 countries support a shift to the safer HFC alternatives
D. they are short-lived in the atmosphere
若要对某点进行比例、旋转变换,首先需要将坐标原点平移至该点,在新的坐标系下做比例或旋转变换,然后在将原点平移回去。()
最常见的关节脱位是()
A. 先天性脱位
B. 外伤性脱位
C. 习惯性脱位
D. 病理性脱位
E. 完全脱位
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