## What's the problem in this numerical integration b...

Maple gives the integral's face instead of giving a number as the numerical integration, no matter what command for the numerical integration I use. Does any one know what the problem is?

```T2start := -5.036645000*10^9*(x[5]^2+.2725890432*x[5]+.3732640349)*x[5]/(5.036645000*10^9*x[5]^2+1.27004241*10^8*x[5]+5.3714241*10^7);
T2end := -5.036645000*10^9*(x[5]^2+.2871403962*x[5]+.3945934083)*x[5]/(5.036645000*10^9*x[5]^2+1.27004241*10^8*x[5]+5.3714241*10^7);
J := (25183225000000*x[5]^4+(-100732900000000*T[2]+73827142410000)*x[5]^3+(-112645777230000*T[2]+662242877289)*x[5]^2-2398770574578*T[2]*x[5]-393671672289*T[2])/(10000000*x[5]^2+14658000*x[5]);
int(abs(J), [T[2] = T2start .. T2end, x[5] = 0 .. infinity], numeric);```

I also used the following.

`evalf(Int(abs(J), [T[2] = T2start .. T2end, x[5] = 0 .. infinity]));`

The result was same.

Or when I use

`evalf(Int(abs(J), [T[2] = T2start .. T2end, x[5] = 0 .. infinity], method = _MonteCarlo));`

It gives an error saying:

Error, (in evalf/int) invalid arguments

## How do I get an exact number out of this function?...

Wus poppin Jimbos

My function is as follows:

f(x)=(10000/1+30762*0.478^x)+5

I can then type

maximize(f'(x))

And I get the result which is approximately 1845.361367

I then assign at a name e.g. "M"

I then try and execute the command (where I isolate the expression for x)

f'(x)=M

I get the result

x = 14.00001597 - 0.00005369289477 I

Which is super annoying to look at..

Is there any way that I can remove the - 0.00005369289477 I part? And just get the answer (which should be 14)

I have no problem executing

diff(f(x), x) = 1845.361366;
=
"(->)"

x = 13.99997555

However 1845.361367 once again gives me x = 14.00001597 - 0.00005369289477 I

Any help is appreciated <3

## how to search matrix ?...

Is it a complete set ? How to search matrix?

## Can I execute multiple worksheets at the same time...

When I tried to execute one of my opened worksheets, the "execute the entire worksheet button" became unactive for the others. I am pretty sure there was an option to execute multiple worksheets in Maple 14. Did the developers remove that in newer versions?

## How can I graph equation?...

u:=(x,t)->Sum(sin(r*Pi*x/20)*(4/(r^2*Pi^2))*sin(r*pi/2)*cos(r*Pi*t/20),r=1...1000);

plot3d(u(x,t),x=0...10,t=0...1);

When I want to draw the graph, it gives a straight line. But this is a wave equation

## How can I simplify this logarithmic expression?...

I am trying to calculate log[1/3](x)-log[sqrt(3)](x^2)+log[x](9) with log[3](x) = a.
I tried:

restart;
sol := solve(log[3](x) = a, x);
f :=x->log[1/3](x)-log[sqrt(3)](x^2)+log[x](9) ;
simplify(f(sol))

I don't get the answer (2-5a^2)/a.

How can I get that answer?

## i have problem in a solve example,int for ,......

hi

i want to solve a example in this picture but i get error.

thanks

1.mw

example

## "a problem was encountered while opening the workb...

Hey, this is not the I've had this encounter. I want to open this saved document but when I open it and Maple starts up it just hits me with "A problem was encountered while opening the workbook. Database is not opened". How can I get to open it properly and see my math notes?

How can this be prevented?

Any help?

Christian

## Wrong output when solving an equation...

Hi.

When I try to solve the equation 15-1/100M=5+1/600M. The result in maple is 7/6000. But the “real” result according to other calculating programs is 6000/7. Is there a setting that is causing this to happen?

## Gibbs Phenomenon Peak Value at Discontinuities...

The Fourier series of waveforms with discontinuties experiences an overshoot near the discontinuity known as the "Gibbs phenomenon".  There is quite a bit of literature showing that the overshoot for a rectangle function is ~ 1.089.  What about other functions such as (1-x) or a decaying exponential for x positive?  Is there any reason to expect the overshoot ratio to be identical to the rectangle function?  I do know for a fact that the behavior of the overshoot is different for the triangle function (1-x) than for the rectangle function.  For low harmonics there is an undershoot for the triangle function case, but this is not the case for the rectangle function.  The overshoot occurs for the triangle function after a sufficient number of terms are included in the Fourier series.  The same is true for the decaying exponential.  This is illustrated in my worksheet linked below.

GIBBS_effect.mw

Does anyone know of MAPLE code that computes the theoretical overshoot if there is an infinite number of terms in the series for different waveforms or functions?

## Contraction in Physics package...

So I have the following:

restart;
with(Physics):
Setup(mathematicalnotation=true,coordinatesystems=cartesian);
Define(A[mu](X));

First of all X ist defined in terms of (x,y,z,t). Is is also possible to define it in terms of (t,x,y,z) with t being mu=0.

When I do

alias(X=(t,x,y,z))

this applies only to this one vector and

d_[4] is still the time differentiation, right?

Then I wanted to construct the divergence

d_[`~mu`] A[mu](X);
TensorArray(%,performsumoverrepeatedindices=true);

This should give me sth like d1 A1 + ... + d4 A4, but it stays with d_mu A_mu ?!?

Why?

Is there also a "function" which does the contraction?

So if I have

f[mu,nu]=d_[mu] A[nu](X)

eval(f[mu,nu],nu=mu)

contract(%)

??

## A simple evalf/Int crashes Maple...

`evalf(Int(x*(1-2*x^(3/10))^(10./3),x=0..1));  # Crashes Maple`

Note that:

int(x*(1-2*x^(3/10))^(10./3),x=0..1);
int(x*(1-2*x^(3/10))^(10/3),x=0..1);

are OK.

(Windows 7, Maple 2017.3, 64 bit)

## 2D Wave Equation Plot3d...

lambda:=unapply(5*Pi*sqrt((m^2)/16+(n^2)/4),m,n):'lambda[m,n]'=lambda(m,n);

u:=(x,y,t)->0.426050*sum(sum((1/(m^3*n^3))*cos(lambda*t)*sin(m*Pi*x/4)*sin(n*Pi*y/2),m=1..infinity),n=1...infinity);

lambda value depends on m and n. m and n are odd numbers. We write 2 * m-1 and 2 * n-1 instead of m and n. x = 0: 0.01: 4 and y = 0: 0.01: 2 and t = 0.01.
How can I draw a 3D plot?
Where do we  write 0.01 in increments of amount?   in the Grid command?Or how do we plot for the direct x = 0 ... 4 and y = 0 .... 2 and t = 0.01?

## Simplifying a procedure...

Hi everyone,

I'm looking for some way to simplify the following procedure:

scm := proc(X, x) global xx;

if 1 <= X and X < 10 then xx := cat(x)

elif 10 <= X and X < 100 then if 1 <= x and x < 10 then xx := cat(0, x) else xx := cat(x) end if

elif 100 <= X and X < 1000 then if 1 <= x and x < 10 then xx := cat(0, 0, x) elif 10 <= x and x < 100 then xx := cat(0, x) else xx := cat(x) end if

elif 1000 <= X and X < 10000 then if 1 <= x and x < 10 then xx := cat(0, 0, 0, x) elif 10 <= x and x < 100 then xx := cat(0, 0, x) elif 100 <= x and x < 1000 then xx := cat(0, x) else xx := cat(x) end if

elif 10000 <= X and X < 100000 then if 1 <= x and x < 10 then xx := cat(0, 0, 0, 0, x) elif 10 <= x and x < 100 then xx := cat(0, 0, 0, x) elif 100 <= x and x < 1000 then xx := cat(0, 0, x) elif 1000 <= x and x < 10000 then xx := cat(0, x) else xx := cat(x) end if

end if

end proc

Any tips? Thank you in advance.

## using of Glerkin method for solving two coupled eq...

Hi

I want to solve these equations in MAPLE, but something goes wrong.

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