A.1/15
B.1/12
C.1/16
D.1/20
[单选题]:1,1/3,1/6,1/10,( )。A.1/15B.1/12C.1/16D.1/20
[试题]1/2,1/6,1/3,2,(),3,1/2A.4;B.5;C.6;D.9
[单选题]:1/3,1/4,1/6,1/12,1/36,()。A.1/72 B.1/144 C.1/216 D.1/432
[单选题]1/3,1/4,1/6,1/12,1/36,()。A.1/72 B.1/144 C.1/216 D.1/432
[主观题]1/6,1/6,1/12,1/24,()A.1/48;B.1/28;C.1/40;D.1/24;
[单选题]:1×3,2×2,1×1,2×3,1×2,2×1,1×3,…第40项为( )A.1×3 B.2×3 C.3×1 D.2×1
[单选题]1×3,2×2,1×1,2×3,1×2,2×1,1×3,…第40项为( )A.1×3 B.2×3 C.3×1 D.2×1
[单选题]过点(2,-3,1)且平行于向量a=(2,-1,3)和b=(-1,1,-2)的平面方程是().A . -x+y+z-4=0B . x-y-z-4=0C . x+y+z=0D . x+y-z+2=0
[主观题]1/2,1/6,1/12,1/30,()A.1/42;B.1/40;C.11/42;D.1/50;
[单选题]-1/7,1/7,1/8,-1/4,-1/9,1/3,1/10,()A . -2/5B . 2/5C . 1/12D . 5/8