## 48 Reputation

14 years, 172 days

## Heat equation problem...

Maple
Hi, I have written the following code in maple.. which I have to compare with the crank-nicolson scheme written in matlab.. that code is well.. but this is not working.. i need to analytically solve the heat equation PDE := diff(u(x,t),t)=1/2*diff(u(x,t),x,x) IBC := {u(x,0)=T0, u(0,t)=0, u(d,t)=0}: vals := {a=1/2, T0=0.1*sin(x), d=pi}: PDE := eval(PDE,vals); IBC := eval(IBC,vals); sol := pdsolve(PDE, IBC) i get this error Error, (in pdsolve/sys) too many arguments; some or all of the following are wrong: [{u(x, t)}, {u(0, t) = 0, u(pi, t) = 0, u(x, 0) = .1*sin(x)}]

## how to solve an ode numerically?...

Maple

hey guys.. i have put input this in maple.. but it doesn't seem to solve it..

ode:= D(D(y(t)))- u*(1-(y(t)^2))*D(y(t)) + y(t)=0;
ics:=y(0)=0.2, D(y)(0)=0;
y(0) = 0.2, D(y)(0) = 0
dsolve({ode,ics},numeric);

Error, (in unknown) invalid input: op expects 1 or 2 arguments, but received 0

## I want both positive and negative values...

Maple

hey guys.. ive been trying to get the root of the following equation.. but watever i do i am getting only the positive value.. and i have another equation which has 5 answers.. but only 1 is being shown.. can u help me out??

>f0:=x->x/(sqrt(x^2 + cos(x-1))):
>f1:=D(f0):
>f2:=D(f1):
>a:=fsolve(f1(x)=0,x);
a:=3.639062685

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