## How to use plot3d command for a parametric equatio...

Hi,

First of all, I'm beginner in Maple.
I want to plot  "M" versus "kc" and "deltah" as a 3D curve (M is real and positive). Intervals of kc and deltah are  given (see attached file). These three parameters (i.e, M,kc,deltah) should satisfiy the following equation:
Eq=-(1-(deltab+deltah))-(1-(deltab+deltah))/(kc-3/2)-deltah/sigmah-deltah/(sigmah*(kh-3/2))-(1/6)*deltab*sqrt(3)*mu*(1/sqrt((M-u0b+sqrt(3)*sqrt(mu*sigmab))**2)+1/sqrt((M-u0b-sqrt(3)*sqrt(mu*sigmab))**2))/sqrt(mu*sigmab)-(1/6)*sqrt(3)*(1/sqrt((M+sqrt(3)*sqrt(sigmai))**2)-1/sqrt((M-sqrt(3)*sqrt(sigmai))**2))/sqrt(sigmai)=0.

Other parameters are as follows:
kh=3, sigmah=4,sigmab=1,u0b=0.05,sigmai=1/300,deltab=1e-6,mu=1836.
3D.mw

## Why is the eval command not working correctly for ...

Hi,
I have a function "w" that the eval command does not gives the correct value of its first derivative at a fixed point. I guess the problem is due to sqrt() terms, but I can't fix it.
eval.mw

## Taylor expantion...

Hi,
I want to calculate the Taylor expansion of an expression with Maple, but there is an error. How can I fix it?
T.mw
Thanks

## How do I solve a set of equations in Maple?...

Hi,

I want to solve a set of ODE(s) by Maple. How do I do that?(Please, see the attached file)
Thanks.

new.mw

## Non-linear Equations...

Hi,

I have three equations in terms of the following variables:

X,Y,X1, X2

How do I get an equation in terms of (X1,X2)  with Maple from Equations 1-3?

E.mw

Hi,

s1.mw

## How do I show animated point on odeplot?...

`restart;`

`with(plots);`

`a:=0.2; b:=0.2; c:=5.7;`

`ode1:=diff(x(t),t)=-y(t)-z(t);`

`ode2:=diff(y(t),t)=x(t)+a*y(t);`

`ode3:=diff(z(t),t)=b+z(t)*(x(t)-c);`

`ic1:=x(0)=-0.7;`

`ic2:=y(0)=-0.7;`

`ic3:=z(0)=1;`

`sol:=dsolve({ode1,ode2,ode3,ic1,ic2,ic3},{x(t),y(t),z(t)},numeric,method=classical[rk4],stepsize=0.10,output=listprocedure);`
`b:=rhs(sol[2]);`

`c:=rhs(sol[3]);`

`d:=rhs(sol[4]);`

```animate (pointplot3d, [ [b(t),c(t),d(t)], symbol=box, color=blue],t=15..100, background = odeplot(sol, [x(t),y(t),z(t)],t=15..100,numpoints=7000),frames=20);```

UPD
And "Error, (in plots/animate) incorrect first argument" BUT if i use classic functions (sin,cos,sqrt) instead of b,c,d - all is well.

For example [sin(t),cos(t),t/10]

For example [b(t),c(t),d(t)]
Error, (in plots/animate) incorrect first argument

## How to plot an equation?...

Hi,
I want to plot an equation, but I couldn't. Who can guide me?

Ra.mw

## Solve an equation...

Hi,

I want to solve an equation(see the attached file) numerically, find  values of M that satisfy this equation and then plot the curve of M versus sigmai for those values of M that satisfy the mentioned equation. How can I do that with Maple?

eq.mw

## How do I solve a set of equations numerically in M...

Hi,

How do I solve numerically this set of equations with the following ICs to plot U1(x), phi(x),diff(phi(x),x) versus x:

diff(U1(x),x)=-diff(phi(x),x)/(U1(x)-T/U1(x));
diff(phi(x),x\$2)=(1+A1*phi(x)+A2*phi(x)**(3/2)+A3*phi(x)**2)-(M1/U1(x));
where

A1:=(2*k-1)/(2*k-3);
A2:=8*sqrt(2/pi)*(beta-1)*k*Gamma(k)/(3*Gamma(k-0.5)*(2*k-3)**(3/2));
A3:=(4*k**2-1)/(2*(2*k-3)**2);
M1=0.1+sqrt(T+(1/A1));
(Gamma is gamma function)

assume, for example, T=0.1, pi=3.14, beta=0.6, k=3.5

ICs:

U1(x=0)=M1, phi(x=0)=0, diff(phi(x=0),x)=0.001.

Thanks.

## Planar dynamical system...

Hi,

Consider the following planar dynamical system(PDS) with parameters r, p1, s, n:
a:=(r+1)*(1+p1*s)/(2*(1-P1))-1/(n^2);
b:=(r+1)*(3-r)*(1-p1*s^2)/(8*(1-p1))-3/(2*n^4);
c:=(r+1)*(3-r)*(5-3*r)*(1+p1*s^3)/(48*(1-p1))-5/(2*n^6);

## Contour plot with Maple...

Hi,

I need to plot a contour plots of x versus f that satisfy two following equations

2.884460657-2.884460657*sqrt(1-.6933705250*x)-5.000000000*f*(1-(1-.8*x)^.2500000000)-(12.50000000*(1-f))*(1-(1-.32*x)^.2500000000) = 0;

1/sqrt(1-.6933705250*x)+1.250000000*f/(1-.8*x)^.7500000000+(3.125000000*(1-f))/(1-.32*x)^.7500000000 = 0

How can I do that by Maple?

If the coefficient of x can be changed from 0.1 to 0.6, what is your suggestion(s) to  repeat the above process for each of these coefficients?

## Finding the intersection point...

Hellow everyone,

Consider the following diffrential equation:

(dA(x)/dx )^2+V(A)=0,
1- How to plot dA/dx vs A?

2- How to find the coordinate of intersection point of f(x)=e-b*exp(x)-c*(1-2*x/c)^(1/2) with df/dx? e,b,c are constants.

## how to do that?...

Considering the follwoing expr:

A(x):=mue+(mun/gama)+(u0^2)-mud*x-mue*exp(x)-(mun/gama)*exp(gama*x)-(u0^2)*(1-2*x/u0^2)^(1/2);

where

mue:=1/(1+alpha+beta);
mun:=alpha/(1+alpha+beta);
mud:=beta/(1+alpha+beta);
u0:=(mue+mun*gama)^(-1/2);
and assuming the values of alpha and beta lie between 0.1..0.6 and gama=15 ro 20.

How do I determine those values of (alpha,beta,gama) satisfying conditions [(3), (4)], [(3), (5)] or [(3),(6)]?

conditions:

A(x[m] <> 0) = 0:

where x_m is an extreme point of A(x) (other than x=0),

d*A(x)/dx, x = x[m] < 0:

d*A(x)/dx, x = x[m] > 0:

d*A(x)/dx, x = x[m] = 0: