——The relation between the two countries gets _________. A war seems to break out soon .——I hope they will make peace with each other .
A:worse and worse
B:better and better
C:more and more peaceful
①函数y= x2 和y=( x )2是同一函数;
②函数f(x﹣1)的定义域为1,2,则函数f(3x2)的定义域为0, 33 ;
③函数y=log2(x2+2x﹣2)的递增区间为(﹣1,+∞);
其中正确的个数为( )
相交两圆的公共弦长为24cm,两圆半径分别为15cm和20cm,则这两个圆的圆心距等于( )