A:mv2/R
B:
C:mg
D:
设二次函数y=x2+ax+b图像与x轴有2个交点,A(x1,0),B(x2,0);且0< x1<1;1< x2<2,那么(1)a的取值范围是____;b的取值范围是____;则(2) b−4a−1 的取值范围是____.
She likes playing ________piano; her brother likes playing ________ basketball.
白天植物光合作用从叶片气孔散失到大气中的气体是( )