The problem had become _____ in his mind, and he could not decide what to do about it.

        A. simplified   B. exaggerated   C. matured   D. isolated

化简：. 化简：.

测定铅锡合金中Pb、Sn含量时,称取试样0.2000g,用盐酸溶解后,准确加入50.00mL 0.03000mol/L的EDTA,50mL水,加热煮沸2min,

设A是n阶矩阵,满足 ,则 _____. 设A是n阶矩阵,满足 ,则 _____.

计算,其中是从点A(3,2,1)到点B(0,0,0)的直线段AB. 计算,其中是从点A(3,2,1)到点B(0,0,0)的直线段AB.

设矩阵A= ,E为2阶单位矩阵,矩阵B满足BA=B+2E,则|B|=_____. 设矩阵A= ,E为2阶单位矩阵,矩阵B

已知 , , 是某二阶常系数非齐次线性微分方程的3个解,则该方程满足条件 的解为y= ________ .

设非负函数y=y(x)(x≥0)满足微分方程xy"-y'+2=0,当曲线=y(x)过原点时,其与直线x=1及y=0围成平面区域D的面积为2,求D绕y轴旋转所得旋