求由方程[img=134x41]17da65377a0f91e.png[/img]所确定的隐函数[img=91x50]17da653782b7d9a.png[/img]的导数。 ( )
A: x*exp(y/x)
B: x*exp(y/x)*(1/x + y/(x^2*exp(y/x)))
C: x*exp(y/x)*(1/x + y/(x^2*exp(y/x)))+x*exp(y/x)
D: (1/x + y/(x^2*exp(y/x)))
A: x*exp(y/x)
B: x*exp(y/x)*(1/x + y/(x^2*exp(y/x)))
C: x*exp(y/x)*(1/x + y/(x^2*exp(y/x)))+x*exp(y/x)
D: (1/x + y/(x^2*exp(y/x)))
举一反三
- 求微分方程[img=101x35]17da5f15503f795.png[/img] 的通解,实验命令为(). A: dsolve(Dy+2*x*y=x*exp(-x^2))ans=C1*exp(-x^2) + (x^2*exp(-x^2))/2 B: dsolve('Dy+2*x*y=x*exp(-x^2)','x')ans=C1*exp(-x^2) + (x^2*exp(-x^2))/2 C: dsolve('Dy+2*x*y=x*exp(-x^2)')ans=C1*exp(-x^2) + (x^2*exp(-x^2))/2
- 实验命令“ syms x y; z=2*exp(x*y)+log(x+y)； zx=diff(z,'x')”的结果是【】. A: 2*exp(x*y)+log(x+y); B: 2* y*exp(x*y)+1/(x+y); C: 2*x*exp(x*y)+1/(x+y); D: 无结果.
- 如下命令中不能实现如下微分方程组[img=327x203]17e443a5d83ce02.png[/img]，在初值条件[img=172x112]17e443a5e2ead01.png[/img]下的特解求解的是： A: [x,y] = dsolve('Dx+5*x+y = exp(t)', 'Dy-x-3*y=0', 'x(0)=1', 'y(0)=0', 't') B: [x,y] = dsolve('Dx+5*x+y = exp(t)', 'Dy-x-3*y=0', 'x(0)=1, y(0)=0', 't') C: [x,y] = dsolve('Dx+5*x+y = exp(t)', 'Dy-x-3*y=0', 'x(0)=1', 'y(0)=0') D: [x,y] = dsolve('Dx+5*x+y = exp(t)', 'Dy-x-3*y=0', 'x(0)=1', 'y(0)=0', 'x')
- 求微分方程[img=143x21]17da5f14490e50e.png[/img]的通解,实验命令为(). A: dsolve(D2y-2*Dy+5*y=sin(2*x),x)ans =exp(x)*sin(2*x)*C2+exp(x)*cos(2*x)*C1+1/17*sin(2*x)+4/17*cos(2*x) B: dsolve('D2y-2*Dy+5*y=sin(2*x)','x')ans =cos(2*x)*(sin(4*x)/17 - cos(4*x)/68 + 1/4) - sin(2*x)*(cos(4*x)/17 + sin(4*x)/68) + C1*cos(2*x)*exp(x) - C2*sin(2*x)*exp(x) C: dsolve(D2y-2*Dy+5*y=sin(2*x),'x','y')ans =exp(x)*sin(2*x)*C2+exp(x)*cos(2*x)*C1+1/17*sin(2*x)+4/17*cos(2*x)
- function y = myfun(x) y(1) = x(2)*exp(x(1)); y(2) = sin(x(1)+x(2)); 上述函数文件调用的正确方式是：