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

数值求积公式(int )_(-1)^1f(x)dxapprox dfrac (2)(3)[ f(-dfrac (1)(sqrt {2)})+f(0)+f(dfrac (1)(sqrt {2)})] 的代数精度为（）

设A是n阶反对称阵（即A^T = -A），且A可逆，则有(）.A. A^T A^-1 = -EB. AA^T = -EC. A^-1 = -A^TD. |A^T| = -|A|

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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)

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(单选题)集合A= (1,2,3,4) ,A上的二元关系:R= ( <1,2> , <2,4> , <3,1> , <3,2> , <4,2> ),则R是自反的.( )A真B假C忽略该选项D忽略此选项

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)

已知 x→0时 x→0 与x→0是等价无穷小求 a

(1)线性方程组 Ax=b 有解的充分必要条件是 __ .

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