5.设线性方程组的增广矩阵是 [ } 1& 0& 7& 2& 1 0& 1& 2& -1& 1 0& -2& -4& 2& -2 0& 0& 0& 1& 5 ] .-|||-则这个方程组解的情况是 () .-|||-(A)有唯一解 (B)无解 (C)有四个解 (D)-|||-有无穷多个解

9.计算下列积分:-|||-(1) (int )_(0)^2pi dfrac (1)(5+3sin theta )dtheta ;-|||-(2) (int )_(0)^2pi dfrac ({sin )^2theta }(a+bcos theta )dtheta (agt bgt 0)-|||-(3) (int )_(0)^2pi dfrac (1)({(a+cos theta ))^2}dtheta (agt 1) ;-|||-(4) (int )_(-infty )^+infty dfrac (1)({(1+{x)^2)}^2}dx ;-|||-(5) (int )_(0)^+infty dfrac ({x)^2}(1+{x)^4}dx =-|||-(6) (int )_(-infty )^+infty dfrac (cos x)({x)^2+4x+5}dx-|||-(7) (int )_(-infty )^+infty dfrac (xsin x)(1+{x)^2}dx =-|||-(8) (int )_(0)^+infty dfrac ({x)^2+1}({x)^4+1}dx

要造一圆柱形油罐,体积为V,问底半径r和高h等于多少时,才能使表面积最-|||-小?这时底直径与高的比是多少?

若向量α,β,γ线性无关,向量组α,β,δ线性相关,则( )A. α必可由β,γ,δ线性表出.B. β必不可由α,γ,δ线性表出.C. δ必可由α,β,γ线性表出.D. δ必不可由α,β,γ线性表出.

若A和B都是n阶非零矩阵，矩阵A存在一个非零n-1阶子式，且AB=O，则秩r(A)= ( ).A. 1B. n-2C. n-1D. n

已知(alpha )_(1)=((1,1,2,2))^T, (alpha )_(2)=((1,-1,4,0))^T (alpha )_(3)=((1,0,3,1))^T,(alpha )_(1)=((1,1,2,2))^T, (alpha )_(2)=((1,-1,4,0))^T (alpha )_(3)=((1,0,3,1))^T,则 (alpha )_(1)=((1,1,2,2))^T, (alpha )_(2)=((1,-1,4,0))^T (alpha )_(3)=((1,0,3,1))^T,能由该向量组线性表示的表达式为（） A (alpha )_(1)=((1,1,2,2))^T, (alpha )_(2)=((1,-1,4,0))^T (alpha )_(3)=((1,0,3,1))^T, B(alpha )_(1)=((1,1,2,2))^T, (alpha )_(2)=((1,-1,4,0))^T (alpha )_(3)=((1,0,3,1))^T,

设函数 f(x) 在 x=0 处可导，则 lim_(h arrow 0) (f(2h)-f(-3h))/(h) = （ ）A. -f'(0) B. f'(0) C. 5f'(0) D. 2f'(0)

48.如果 A2-6A=E，则 A-1=( )。A. -3EB. A+3EC. A+6ED. A-6E

曲线圆度,通常以曲线半径R、切线长T、正矢f的几何关系来检验。A. 正确B. 错误

求隐函数的导数 设函数 y = y(x)由方程 y = sin (x + y)所确定，则 dy div dx = _ A. sin (x + y)÷ 1 - sin (x + y) B. cos (x + y)÷ 1 - cos (x + y) C. sin (x + y)÷ 1 - cos (x + y) D. cos (x + y)÷ 1 - sin (x + y)

热门问题