## How do I connect to MSQL in Maple?...

Asked by:

I'm having trouble connecting from Maple on Windows 10 to MSQL Server. I tried Microsoft recommended drivers such as sqljdbc_6.4.0.0, did (as I thought) all required steps. The only invariable result I get is "Cannot load driver". I was wandering if anyone had implemented such a construction. Driver name & version , connection string and Java version would be greatly appreciated. Another option is to have any driver, which connects to any of standard databases (Oracle, MySQL).  The only limitation is- it must be from Windows 7 or 10.
Thanks.
A.B.

## Starting a new java session...

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I remember there was a command that used to start an independent java session each time. I thought it's "xmaple -singlemode" but it's not. So could anybody please remind me what was the command. I just killed a second java session after losing kernel connection and java running wild. I'd be very happy to do my calculation in another java session so that if anything goes bad II won't have to open all my 5 tabs again.

## Bug using Heaviside and PDF in statistics package...

Asked by:

Integrating a positive definite function (normal distribution) and a >= 0 function (Heaviside) should not return a negative value.

with(Statistics);
X := RandomVariable(Normal(1, sqrt(2.25)));
int(PDF(X, x)*Heaviside(x^7-5*x^4-3*x+1), x = -infinity .. infinity);
-0.08507120131

Bug.mw

## Show ODE solution step by step...

Asked by:

I'm using dsolve command to solve a differential equation. Using infolevel to 3 will tell me the classification of said DE. However, how can I see the step by step solution? I'm using Maple as a study tool so I do solve manually a DE then I'd like to compare my answer with Maple's. How can I acomplish this? Thanks in advance.

## Students discount...

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Please may I know if you can offer ma student's discount ob the seleted version.

Thank you.

Fred.

Asked by:

## I can't do even basic stuff on maple, what is goin...

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I open a completely new document, type in a few simple expressions and get this weird complex number out. Can someone pleas help me fix this?

## Recursive Assignment Errors...

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Is there any way we can get maple to tell us which variable we are recursively assigning?

## Why is this an error?...

Asked by:

solve({-infinity < a , a < -1, -1 < b ,  b < 0});

## Why is this piecewise plot giving an error? Pls he...

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f(x) := piecewise(0 < x, x^(3/2)*sin(1/x), x = 0, 0, undefined);
plot(f(x));

gives me the following error:

Error, (in plot) incorrect first argument piecewise(0 < x, (HFloat(2.739493386336394e-116)+HFloat(2.739493386336394e-116)*I)*x^(3/2), x = 0, 0, undefined)

I just want to see the function plot. With Wolfram Alpha this is no deal at all!

## Statistics fails to reject invalid parameter value...

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Maple doesn't completely check the condition on the number of trials "n" for Binomial and NegativeBinomial distributions (package Statistics).
The attribute "Conditions" explicitely says that n must be a strictly positive integer but no strictly positive real valuereturna an error (ok, it would be stupid to set n to a non integer value !!!).

I think it is a default that ought to be corrected in future releases (this default still exists in Maple 2018)

 > restart
 > kernelopts(version)
 (1)
 > with(Statistics):

BINOMIAL DISTRIBUTION

 > X := RandomVariable(Binomial(n, p)): L := [attributes(X)][3]: A := exports(L)
 (2)
 > L:-Conditions
 (3)
 > # Maple should return an error for N is not of type posint # # It seems that Sample uses floor(N) N := 10.49; type(N::posint); P := 1/2: X := RandomVariable(Binomial(N, P)): Mean(X), N*P; ProbabilityFunction(X, k); S := Sample(X, 10^6): Mean(S); # A non consistent result (only non negative values of k should be accepted) eval(ProbabilityFunction(X, k), k=evalf(Pi));
 (4)

NEGATIVE BINOMIAL DISTRIBUTION

 > X := RandomVariable(NegativeBinomial(n, p)): L := [attributes(X)][3]: A := exports(L): L:-Conditions
 (5)
 > N := 10.49: P := 1/2: X := RandomVariable(NegativeBinomial(N, P)): Mean(X)

Download BinomialLaw.mw

## When i type sqrt(25), i get 1.81847767202745*10^(-...

Asked by:

Yeah, i have tried evalf[10](sqrt(25)).
How can i get a simple number as answer? I'm loving the software but i just wished i could type in:
int(sin(x), x = 0 .. pi)
and get 2 instead of (2.739493386*10^(-116) + (2.739493386*10^(-116))*I)*pi.
Also, when i type evalf[50](pi), i wish to get all the 50 digits, but i just get \pi :/.
Please help me.

## How to solve initial Newton iteration is not conve...

Asked by:
I want to solve an ODE system numerically, but maple show not converge for iteration, can you give a solution
with(VectorCalculus);
with(linalg);

pi := 4; eta := 6; mh := .1; mv := .3; bh := .15; Nh := 400; Nv := 200; bv := .25; b := .8; d := .1; p := .5; B := 10; A := 1; alpha := .25; beta := .7; K := 400; r := .5; c := .9; q := .8; Sh0 := 225; Sv0 := 100; Ih0 := 175; Iv0 := 600; P0 := 50; T := 35; B := 10;

eq1 := diff(L1(t), t) = -L1(t)*(-bh*b*Iv(t)/Nh-mh)-L2(t)*bh*b*Iv(t)/Nh; eq2 := diff(L2(t), t) = -L2(t)*(-mh-d)+L3(t)*bv*b*Sv(t)/Nv-L4(t)*bv*b*Sv(t)/Nv; eq3 := diff(L3(t), t) = -(L4(t)*Iv(t)+L3(t)*Sv(t))*L3(t)/(2*B^2)-L3(t)*(-bv*b*Ih(t)/Nv-mv-L3(t)*Sv(t)/(2*B^2)-(L4(t)*Iv(t)+L3(t)*Sv(t))/(2*B^2)-P(t)*alpha)-L4(t)*(bv*b*Ih(t)/Nv-L3(t)*Iv(t)/(2*B^2))-L5(t)*P(t)*alpha; eq4 := diff(L4(t), t) = -A-(L4(t)*Iv(t)+L3(t)*Sv(t))*L4(t)/(2*B^2)+L1(t)*bh*b*Sh(t)/Nh-L2(t)*bh*b*Sh(t)/Nh+L3(t)*L4(t)*Sv(t)/(2*B^2)-L4(t)*(-mv-L4(t)*Iv(t)/(2*B^2)-(L4(t)*Iv(t)+L3(t)*Sv(t))/(2*B^2)-P(t)*alpha)-L5(t)*P(t)*alpha; eq5 := diff(L5(t), t) = L3(t)*Sv(t)*alpha+L4(t)*Iv(t)*alpha-L5(t)*(r*(1-P(t)/Nv)-P(t)*r/Nv+alpha*(Sv(t)+Iv(t))-q*c); eq6 := diff(Sh(t), t) = pi-bh*b*Sh(t)*Iv(t)/Nh-mh*Sh(t); eq7 := diff(Ih(t), t) = bh*b*Sh(t)*Iv(t)/Nh-mh*Ih(t)-d*Ih(t); eq8 := diff(Sv(t), t) = eta-bv*b*Sv(t)*Ih(t)/Nv-mv*Sv(t)-P(t)*Sv(t)*alpha-L3(t)*Sv(t)^2/(2*B^2)-L4(t)*Sv(t)*Iv(t)/(2*B^2); eq9 := diff(Iv(t), t) = -L3(t)*Sv(t)*Iv(t)/(2*B^2)+bv*b*Sv(t)*Ih(t)/Nv-mv*Iv(t)-P(t)*Iv(t)*alpha-L4(t)*Iv(t)^2/(2*B^2); eq10 := diff(P(t), t) = P(t)*r*(1-P(t)/Nh)+P(t)*alpha*(Sv(t)+Iv(t))-q*P(t)*c

fcns := {Ih(t), Iv(t), L1(t), L2(t), L3(t), L4(t), L5(t), P(t), Sh(t), Sv(t)}; a := dsolve({eq1, eq10, eq2, eq3, eq4, eq5, eq6, eq7, eq8, eq9, Ih(0) = Ih0, Iv(0) = Iv0, L1(T) = 0, L2(T) = 0, L3(T) = 0, L4(T) = 0, L5(T) = 0, P(0) = P0, Sh(0) = Sh0, Sv(0) = Sv0}, fcns, type = numeric);
fcns := {Ih(t), Iv(t), L1(t), L2(t), L3(t), L4(t), L5(t), P(t),

Sh(t), Sv(t)}
Error, (in dsolve/numeric/bvp) initial Newton iteration is not converging



## platform for running calculation...

Asked by:

Does maple provide any platform for running calculation something like cloud facility

## Severe basic bug in Maple 2019.1 in Document Mode?...

Asked by:

Dear Maple users

Some students have come to us to report, that something doesn't seem to work properly in Maple 2019.1 in Document Mode. And they seem to be right: writing an passive math formula by using Shift+F5 (the formula is gray, not blue), then using F5 to get out of that Math field and back into Text Mode. Using the Enter key to go to the next line: It doesn't work! The cursor stays in the same line. This behavior is new in Maple 2019. It worked properly in Maple 2018 and earlier. I assume it is not the intention?

I know it can easily be dealt with by making a new Paragraph by using the shortcut Ctrl+Shift+J. I call the assumed bug 'severe' though, because it will severely delay the workflow for many students. They are used to deliver a document mixed with formulas (active or passive) and text.

NB! I have tested it on several computers (Mac and Windows), and it doesn't work on any of them.

Regards,

Erik V.

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