• 2021-04-14
    【单选题】在 MATLAB 命令窗口中 , 键入命令 syms x ; int(x*sin(x)) 。结果是
    A. ans= sin(x)-x*cos(x) B. ans= cos(x)+x*sin(x) C. ans= sin(x)-cos(x) D. ans= -1/2*cos(x)*sin(x)+1/2*x
  • ans= sin(x)-x*cos(x)

    内容

    • 0

      求微分方程[img=634x60]17da653955cf9e7.png[/img]的特解。 ( ) A: sin(2*x)/3 - cos(x) - cos(x)/3 B: sin(2*x)/3 - cos(x) - sin(x)/3 C: cos(2*x)/3 - cos(x) - sin(x)/3 D: sin(2*x)/3 - sin(x) - sin(x)/3

    • 1

      17e0b849d3a4a3b.jpg,计算[img=19x34]17e0ab14a855463.jpg[/img]的实验命令为( ). A: syms x; f=diff((1+sin(x)^2)/cos(x),1)f=2*sin(x) + (sin(x)*(sin(x)^2 + 1))/cos(x)^2 B: f=diff((1+sinx^2)/cosx,1)f=1/2/x^(1/2)/(1-x)^(1/2) C: syms x;f=diff((1+sinx^2)/cosx,1)f=2*sin(x) + (sin(x)*(sin(x)^2 + 1))/cos(x)^2

    • 2

      $\int {{1 \over {3 + 5\cos x}}} dx = \left( {} \right)$ A: ${1 \over 4}\ln \left| {{{2\cos x + \sin x} \over {2\cos x - \sin x}}} \right| + C$ B: ${1 \over 4}\ln \left| {{{2\cos {x \over 2} + \sin {x \over 2}} \over {2\cos {x \over 2} - \sin {x \over 2}}}} \right| + C$ C: $\ln \left| {{{\cos {x \over 2} + \sin {x \over 2}} \over {\cos {x \over 2} - \sin {x \over 2}}}} \right| + C$ D: $\ln \left| {{{\cos x + \sin x} \over {\cos x - \sin x}}} \right| + C$

    • 3

      函数\(y = { { \sin x} \over x}\)的导数为( ). A: \( { { x\cos x - \sin x} \over { { x^2}}}\) B: \( { { x\cos x + \sin x} \over { { x^2}}}\) C: \( { { x\sin x - \cos x} \over { { x^2}}}\) D: \( { { x\sin x + \cos x} \over { { x^2}}}\)

    • 4

      求函数[img=107x38]17da6537b12a2e0.png[/img]的导数; ( ) A: 2*x*sin(1/x) - sin(1/x) B: 2xsin(1/x) - cos(1/x) C: 2*x*sin(1/x) - cos(1/x) D: 2*x*cos(1/x) - cos(1/x)