((x)^2) D. (x)^2f((x)^3)
dfrac (1)(x) C. -dfrac (1)({x)^2} D. dfrac (2)({x)^3}
在空间直角坐标系下母线平行于 z 轴 的柱面方程是 A (x)^2-2(y)^2+z=0B (x)^2-2(y)^2+z=0.C (x)^2-2(y)^2+z=
-x-|||-C.2x-|||-D. -2x
(x)^2+bx+c C. (a(x)^2+bx+c) D. ^2(a(x)^2+bx+c)
((X)_(1)+(X)_(2)+(X)_(3))/3 b.X1-|||-c. ((X)_(1)+(X)_(2))/2 d. (2(X)_(1)+(X)_(2)
二次型 ((x)_(1),(x)_(2),(x)_(3))=2({x)_(1)}^2+2({x)_(2)}^2+2({x)_(3)}^2-2(x)_(2)(x)
(3) int dfrac (x)(sqrt {2-3{x)^2}}dx;
1/2-|||-x C. -1/2-|||-D. -2
int dfrac (x)(sqrt {2-3{x)^2}}dx。。