Hi!

This question is related to http://www.mapleprimes.com/questions/204419-Derivatives-Of-Splines-Are-Not-Defined and http://www.mapleprimes.com/questions/42114-Problem-With-Spline-Integrating , however I have not been able to apply the solutions given there to my problem.

I have a set of points given by

and certain function value points given by

where e1 is the function I am approximating.

Using

I come up with my piecewise function.

When I do diff(e4,x), however, the points at the nodes show "float(undefined) x=0.2..."(the node).

As it turns out, the value of the derivative on the left of the node is not equal to that of the right side by a factor of 10^(-7), in other words, numerically unimportant but high enough for maple to realise it is not the same number. How could I tell Maple that I am happy choosing, for example, the value given by the function on right side of the node?

I welcome any suggestions.

Many thanks in advance.

Every time I try to write a procedure I get stuck.

This time is no different:

restart;

global a:=0.081819221, PI:=3.1415926535897932384626433832795;
Ecce:=proc(lt)
lat:=lt*(PI/180);
b:=((1-a*sin(lat))/(1+a*sin(lat)))^(a/2));
t:=ln((tan(PI/4)+lat/2));
d:=3437.7468*t*b;
return d;
end proc;

I digit the following to get a result
Ecce(45.2112);

and this is what I get (in blue)
Ecce(45.2112)

Every single time. I can never have a procedure that works right away. It's getting on my nerves

I want to extract all the symbols and last trade from 

http://finance.yahoo.com/q/cp?s=%5EIXIC

I have tried:

status, data, headers := HTTP:-Get("http://finance.yahoo.com/q/cp?s=%5EIXIC");
data;

but it just gives me a bunch of jiberish! Any ideas?

The equation tan(y) = 2*tan(x) defines y implicitly as a function of x.  Well, perphas "defines" is too strong a word, since there are multiple solutions for y.  However, if I am not mistaken, there exists a unique continuous solution y(x) that goes through the origin, that is, y(0)=0, and is defined for all x.

Question 1: How do we plot the graph of y(x)?

I have a roundabout solution as follows.  Differentiate the equation tan(y(x)) = 2*tan(x) with respect to x and arrive at a first order differential equation in y(x).  Solve the differential equation with the initial condition y(0)=0.  Surprisingly, Maple obtains an explicit solution:

which we can plot:

plot(rhs(%), x=0..2*Pi);

Question 2: Is there a neat way of getting that solution with algebra only, without appealing to differential equations?

please i would love make a 3d plot of this Bessel function expression against the parameter p and T[0] using maple (p^(((2+deltaT[0])/(2)))*(C[1]*BesselJ((delta)/(-2)*sqrt(T[0]-4 T[g]),(-((T[g])/(T^(2)[0])*gamma*G*delta*sqrt(alpha*k))/(p))+C[2]*BesselY((delta)/(-2)*sqrt(T[0]-4 T[g]),(-((T[g])/(T^(2)[0])*gamma*G*delta*sqrt(alpha*k))/(p)) where [delta = 0.2e-2, T[g] = (1.1, .615, .48, .2962), k = (1.2, 1.3, 1.4, 1.5), G = .2, gamma = .2, alpha = 5.36, C[1] = 500, C[2] = 100,p = (.22, .23, .24, .25), T[0] = (3.666667, 2.307692, 1.714286, 1.377778)

we can get the continued fraction of cot(x) with the command

> convert(cot(x), confrac, x, 6)

the result is

(1+x^2/(-3+x^2/(5-(1/7)*x^2)))/x

how could I convert this result to a form like

1/x-(1/10)*x+49*x/(20*x^2-210)

I have some excel data which I need to fit in the formula:

0.5a*erfc(0.5*2^0.5*(-x+m1/s1)) + (0.5-0.5a)*erfc(0.5*2^0.5*(-x+m2/s2))

In this formula the coefficient m ans s are mean and standard deviation and a is the weigth of 2 peak in a cummulative gaussian distribution.

I fitted this (I will insert the maple file) and found:

-48736.43 erfc(-0.707x + 0.707) + 48736.43 erfc(0.707x + 0.707)

Can this be correct?

And how do I find the values of m1, s1, m2, s2 and a?

data.xlsx

data_fit.mw

I want to solve numerically the nonlinear pde:

u_x+u_t - (u_{xt})^2 = u(x,t)

which method do you propose me to use with maple? (I don't mine about which boundary conditions to be used here).

Hello.
Have a question for use Physics[TransformCoordinates] . For example, in a Cartesian coordinate system is an arbitrary tensor. As you know, in this case the covariant, contravariant and mixed components are the same. We have a coordinate transformation such as transforming our Cartesian coordinate system in the oblique coordinate system. In this simple example, correctly calculated the covariant, contravariant and mixed components (structure: covariant and contravariant), but other mixed components (structure: contravariant and covariant) are calculated is not correct. I checked by hand.

Download Transformation_tensor_components.mw

I have a function fitted and found the coeffiecients, the coeffiecient values are found with data from maple

the function is: a*(x+b/c)

my result is 5x+15

How do I get the values of a, b and c? The value of a is 5 that I know, but how does I get that maple gives me all the values of a,b  and c? The problem is that I get one value while i need the values of a, b and c.

Thanks

I recently got myself a 64 bit computer and have noticed that I cannot use the option compile=true in dsolve/numeric. Take the following simple example:

dsolve({diff(x(t),t)=x(t),x(0)=1},numeric,compile=true);
Error, (in dsolve/numeric/SC/preproc) unable to compile (rc=1), please try again, and if that fails verify your Windows compiler installation

I'm using Windows 10, but had the same problem with Windows 8.1 on the same machine.
The Compiler:-Compile examples in the help page all work.

What do I have to do to make the option compile=true work in dsolve/numeric?

You may safely assume that I don't know any technicalities about these things.

hi, I am tyying to solve this equation but there is arising an error, plz help me,
VIM.3rd_order.mw

How to build a discrete probability distribution with the function with two variables below?

ff := (x,y)->piecewise(x = 0 and y = 0, 1/8, x = 0 and y = 1, 1/6, x = 1 and y = 0, 1/3, x = 1 and y = 1, 3/8);

Thank you for your help.

Oliveira.

ca:= [a, b, a, a, b, b, b, a, a, a, c, a, c, c, a, a];

I started using Maple for a short time and do not know all the functions and commands. How to split the above list as follows:

[[a], [b], [a, a], [b, b, b], [a, a, a], [c], [a], [c, c], [a, a]]

Thank you for help.

Oliveira.

How to change the font style, globally, the inputs and outputs of computations in Maple 2015? That is, every time a new document is started, the chosen style is automatically applied.

Oliveira.