janhardo

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These are questions asked by janhardo

I following a example of products multiplication like this one

u:=n->Product(2*k-1,k=1..n)/Product(3*k-1,k=1..n)*x^n;

Calculating with  this with maple 1d input is correct, but when i convert a maple 1d input  to 2D input ( i did somewhere) and use this then there is difference with the maple 1d calculation

Seems to be not a advisable to use converted maple 1d to 2 D input for calculation : ( for a mixed calculation(maple input/2D input)  or solely 2d input) , but only for purpose of seeing what the expression in maple input is standing for.   

Note: i did the calculation again with mixed input and now the correct sequenze of answers shows up ?

The prime notation as used default on my keyboard is not the same as used in Maple.

NULL

restart;

with(student):

interface(typesetting = extended);

extended

(1)

Typesetting:-Settings(typesetprime = true);

true

(2)

diff(y(x), x)

diff(y(x), x)

(3)

y*`\`   `and  diff(y(x), x)are not working on my keyboard as prime?

 prime symbols (not showed)  not as (3)

 ========================================

restart

kernelopts(version)

`Maple 2021.1, X86 64 LINUX, May 19 2021, Build ID 1539851`

(4)

interface(typesetting = extended)

diff(y(x), x)

diff(y(x), x)

(5)

Typesetting:-Settings(typesetprime = true)

diff(y(x), x)

diff(y(x), x)

(6)

"y^((3))"

diff(diff(diff(y(x), x), x), x)

(7)

PDEtools:-declare(y(x))

y(x)*`will now be displayed as`*y

(8)

diff(y(x), x)

diff(y(x), x)

(9)

"y^((3))"

diff(diff(diff(y(x), x), x), x)

(10)

PDEtools:-declare(f(x, y))

f(x, y)*`will now be displayed as`*f

(11)

diff(f(x, y), y, x, y)

diff(diff(diff(f(x, y), x), y), y)

(12)

=================================================

Application Differential equation :  

int((10000*k/(100*k*P(t) - 1) - 100/P(t))*diff(P(t), t), t = 0 .. t) = t;

int((10000*k/(100*k*P(t)-1)-100/P(t))*(diff(P(t), t)), t = 0 .. t) = t

(13)

P(t)=solve(%,P(t));

Error, (in solve) cannot solve expressions with diff(P(t), t) for P(t)

 

This error .. see  Applications to Differential Equations

Applications to Differential Equations

   

 

NULL

Download vraag_over_dv_in_harald_pleym_-error_.mw

Also a error in old studymaterial : how to be fixed ? ...or obselote now this calculation and must be replaced for a modern calculation in Maple ?

Thought always that the round d is reserved for function of two variables x,y , but  that seems to be not the case here ?

restart;

Comparing Different Answers

 

Een antwoord ergens gegeven is

Int(sqrt(x^2+1), x) = (1/2)*x*sqrt(x^2+1)+(1/2)*ln(x+sqrt(x^2+1)) + C                                                             (vb)

 

Mple geeft

 

Int(sqrt(x^2+1),x)=int(sqrt(x^2+1),x)+C[1];

Int((x^2+1)^(1/2), x) = (1/2)*x*(x^2+1)^(1/2)+(1/2)*arcsinh(x)+C[1]

(1)

 

De twee antwoorden lijken nog niet opelkaar !
In het gegeven antwoord staat er een ln en in Maple kan een expressie omgezet worden in ln termen
  

convert(%,ln);

Int((x^2+1)^(1/2), x) = (1/2)*x*(x^2+1)^(1/2)+(1/2)*ln(x+(x^2+1)^(1/2))+C[1]

(2)

(2)  is hetzelfde (vb)

Dezelfde integraal i sook gegeven als

Int(sqrt(x^2+1),x)=((x+sqrt(x^2+1))^2+4*ln(x+sqrt(x^2+1))-(x+sqrt(x^2+1))^(-2))/8+C[2];

Int((x^2+1)^(1/2), x) = (1/8)*(x+(x^2+1)^(1/2))^2+(1/2)*ln(x+(x^2+1)^(1/2))-(1/8)/(x+(x^2+1)^(1/2))^2+C[2]

(3)

Controle

een effectieve manier om twe antwoorden t evergelijken voor hetzelfde probleem is het verschil te berekenen van een vergelijking met de twee integralen

#lhs(%);

#rhs(%%);

 

#diff(lhs(%)-rhs(%)=0,x);

NULL

#diff(f,x);

diff(lhs(%)-rhs(%)=0,x);

(x^2+1)^(1/2)-(1/4)*(x+(x^2+1)^(1/2))*(1+x/(x^2+1)^(1/2))-(1/2)*(1+x/(x^2+1)^(1/2))/(x+(x^2+1)^(1/2))-(1/4)*(1+x/(x^2+1)^(1/2))/(x+(x^2+1)^(1/2))^3 = 0

(4)

simplify(%);

0 = 0

(5)

Strange that  diff(lhs(%)-rhs(%)=0,x);  is translated by 2 d input with round d notation for functions with two variables ?
The two integrals are functions of one variable
diff(f, x)

Download Controleren_dezelfde_antwoord_voo_expressies.mw

Sometimes its easier when doing math in maple input mode to use first the 2d maple input mode and convert this to maple input
Is there a hotkey assigned in Maple to do this toggling from 1d input to 2d input ( also from 1d output to 2d output  )

Now it must be done by mouse

This is so useful to see geometrical mapping diagram to visualize Complex analysis

Something that also can be made for Maple 

Mapping Diagram for Cauchy Integral Formula – GeoGebra

Using GeoGebra for visualizing complex variable. (google.com)

I highly encourage everyone interested in complex variable to read Tristan Needham „Visual Complex Analysis” and try to solve problems with or without aid of GeoGebra. I hope that in this workshop we will manage to get a feeling of complex functions and as a final point understand how complex integration works. It is a common misconception that complex integration can't be visualized, and using Tristan Needham's ideas we will try to explore this idea. It's a pity that we don't have a lot of time, thus we will skip a lot of important information and construct only some graphs. 

There is so much experimenting with Geogebra software and doing too this in Maple ?

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