I get explicit solution not found , how to view the solution ?
显示 更早的评论
syms x(t) y(t)
dx = diff(x,t)
dx2=diff(x,t,2)
dy = diff(y,t)
dy2=diff(y,t,2)
eqns = [dx2 + dx2 == y - 2*dx*dy + 2*(dx).^2+cos(t), dy2 == 2*y + x*dy];
conds = [y(0)==0, dy(0)==1, x(0)==0, dx(0)==0];
sol = dsolve(eqns,conds)
12 个评论
Jan
2018-5-19
What is your question? Did you take into account, that this function might not have an explicit solution?
madhan ravi
2018-5-19
madhan ravi
2018-5-19
编辑：madhan ravi
2018-5-19
Stephan
2018-5-19
Have a look at this:
Does this help you?
Best regards
Stephan
Star Strider
2018-5-19
madhan ravi
2018-5-19
编辑：madhan ravi
2018-5-19
Stephan
2018-5-19
Sorry,
but this is not the homework service here...
Best regards
Stephan
Walter Roberson
2018-5-19
You made a mistake in the equations. The second equation has y'' on the left hand side, but you used dx2 which is x'' .
madhan ravi
2018-5-19
madhan ravi
2018-5-19
Jan
2018-5-19
Please post the code as text. We cannot scroll to the right on your screenshot.
madhan ravi
2018-5-22
采纳的回答
Walter Roberson
2018-5-20
If you temporarily leave out the conditions on the derivatives, then Maple says that the solution is
x(t) = -ln(-2*(-(1/2)*MathieuC(0, -1, (1/2)*t)-_C2*MathieuS(0, -1, (1/2)*t))/(MathieuSPrime(0, -1, (1/2)*t)*MathieuC(0, -1, (1/2)*t)-MathieuCPrime(0, -1, (1/2)*t)*MathieuS(0, -1, (1/2)*t)))-(2*I)*Pi*_Z1
y(t) = 0
where _Z1 is an arbitrary integer (that is, there is a family of solutions spaced 2*Pi*I apart) and _C2 is a constant of integration.
Now let us consider dy(0)==1 . But y(t) is the constant 0, so dy is the constant 0, so dy(0) can never be 1.
The system is potentially inconsistent. (I say "potentially" because Maple does not always find all of the potential solutions.)
The condition dx(0)=0 is fine: it can be resolved as _C2 = 0
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