已知|a|=2,|b|=
,且a?b=3,则|a×b|等于()
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[单选题]已知|a|=1,|b|=,且=π/4,则|a+b|等于:()A . ['1B . 1+C . 2D .
3.已知向量a,b满足|a|=1,|a+2b|=2,且(b-2a)⊥b,则|b|= ( )A. $\frac{1}{2}$B. $\frac{\sqrt{2
已知a,b为正实数,且 +2a+b=16, 则 () .已知a,b为正实数,且 +2a+b=16, 则 () .
已知有矩阵A_(2times 3),B_(3times 4),则下列()运算可行。A. $A + B$B. $A - B$C. $AB$D. $BA$
已知a>0,b>0,且2a+b=2,则( )A. ab的最小值是$\frac{1}{2}$B. $\frac{1}{a}+\frac{2}{b}$的最小值是4C
设A,B都是3阶方阵,且|A|=-3,|B|=2,则|-2A^TB^T|等于____.10.(2.0分)设A,B都是3阶方阵,且$|A|=-3$,$|B|=2$
设 a = ( -2 , 4 , -2 ) , b = ( 2 , -7 , 4 ), 则 3 a + 2 b 等于( )设a=(-2,4,-2),b=(2,
设 a = (2, 4, 1), b = (-2, 3, -1)则 2a - 3b 等于( )A. (-10,-1,5)B. (10,-1,-5)C. (10,
[单选题]已知a=2,b=,a·b=2,则a×b为().A . 2B . 2C . 4D .
4.已知正实数a,b,且a+2b=2,则(1)/(a+1)+(a+1)/(2b+1)的最小值是() A.2 B.(3)/(2) C.(5)/(4) D.(