• 2022-07-26
    如图[tex=3.0x1.286]AY2ol2cPDK1dH7saqWGeng==[/tex]所示.已知抛物线方程为[tex=10.643x2.5]XVoffNK7/ZLSsTqpTSuf9IhqF0f5nVd+5XGUiXI3EPvrqzKl9yePM2k72H92SZ7+LZnskuKwCNniTISNK8/cwg==[/tex]、试求面积[tex=2.286x1.0]Tcj01eFz1bK02iLqEBdmYg==[/tex]的重心坐标。[img=725x209]17d0322219d0be4.png[/img]
  • 解 由已知得[tex=3.714x2.143]vSUNwvQxSrHd1N7OF4fJbdfcmYuMXfna5Uk3abA0Kqk=[/tex]. 从而[tex=26.071x9.071]tZgoKu0h0avyTPXKwHnsENDrRxsaN0G8tUFkcIduXJwzua98anCLcRzacCu/gVre2Yb1bpjQIGqvSl4dKURvic2/ZypvgHj7fsnQySIbgklJJPfUkVCsWzO6RVrbcI1uLj5Y7O4cSFuogDdIa7L8FDymjU5BT3pyo5LkTF4PDn3iSgIiBc2poMD8BrlOYrjXEZ3bvnxy2vA/hH0RNcbw3hMPhQ9dMn7sMyo8Rf5p5LmD2pLK84UuqrTNVWLctOIpUGzho5p/m3im69qou4hcNcGT7hul3ud9zGyRLs1a+RCwLd8u3vrraumAFMlCalboEe4WbZyctxaexIkFs6MA9rnCxvcdRNfUb2L9nG5g8kEjPDDazbQr9yvo8uuOaFqJEJLyJeQHRsO/wqQYc02SEyphxDByPS1JS9q/uzmM0b8=[/tex]因此[tex=12.357x2.429]XH/13MiijusRQKLVFfn5pyPFq3f9sbQeEtNYugwHY3iAaL68GofLSbzVyQVZ6yWnJskm5h8th1RaFHG7m8ro2nH8ooS7ZWUydTjxs+mByzudX5nPXfoJKFl6BAPddB8W[/tex]

    内容

    • 0

      【单选题】设X为连续型随机变量, 其概率密度: f(x)=Ax2, x∈(0,2); 其它为0. 求(1)A=(); (2) 分布函数F(x)=(); (3) P{1<X<2} (10.0分) A. (1)3/8; (2)x<0,    F(x)=0; 0≤x<2, F(x)=1/8x³; x≥2,  F(x)=1; (3) 7/8 B. (1)5/8; (2)x<0,    F(x)=0; 0≤x<2,   F(x)=1/8x³; x≥2,    F(x)=0 (3) 1/8

    • 1

      采用基2频率抽取FFT算法计算点序列的DFT,以下()流图是对的。 A: x[0],x[1],x[2],x[3],x[4],x[5],x[6],x[7] B: x[0],x[2],x[4],x[6],x[1],x[3],x[5],x[7] C: x[0],x[2],x[1],x[3],x[4],x[6],x[5],x[7] D: x[0],x[4],x[2],x[6],x[1],x[5],x[3],x[7]

    • 2

      【单选题】Which of the following matrices does not have the same determinant of matrix B: [1, 3, 0, 2; -2, -5, 7, 4; 3, 5, 2, 1; -1, 0, -9,-5] A. [1, 3, 0, 2; -2, -5, 7, 4; 0, 0, 0, 0; -1, 0, -9, -5] B. [1, 3, 0, 2; -2, -5, 7, 4; 1, 0, 9, 5; -1, 0, -9, -5] C. [1, 3, 0, 2; -2, -5, 7, 4; 3, 5, 2, 1; -3, -5, -2, -1] D. [1, 3, 0, 2; -2, -5, 7, 4; 0, 0, 0, 1; -1, 0, -9, -5]

    • 3

      设随机变量X的密度函数为[img=572x74]1791bc8f97085d2.jpg[/img]试求:(1)常数A;(2)[tex=6.714x1.357]AyFmD19eLybEpNdIrC346g==[/tex]

    • 4

      假设“☆”是一种新的运算,若3☆2=3×4,6☆3=6×7×8,x☆4=840(x>0),那么x等于: A: 2 B: 3 C: 4 D: 5 E: 6 F: 7 G: 8 H: 9