## 490 Reputation

10 years, 94 days
Maple is to me difficult. The first version I bought was Maple9, and it was more than 15 years ago. But, I couldn't use it, feeling it too difficult. But, three years ago, I thought Maple might be helpful to my study, and since then, I have continued to learn Maple. As I got able to read the Maple help, I think that I could get to use maple better now than before. But, I feel that I am a beginner yet.

## Real solution x of equation y=x^3...

Maple 2015

Hello people in mapleprimes,

I tried to solve y=x^3 for x, expecting of getting a result of x^(1/3),

through using restart;assume(x::real,y::real);
b:=y=x^3;
solve(b,x);

But, the result was:

Warning, solve may be ignoring assumptions on the input variables.
(1/3)    1  (1/3)   1    (1/2)  (1/3)
y     , - - y      + - I 3      y     ,
2          2

1  (1/3)   1    (1/2)  (1/3)
- - y      - - I 3      y
2          2

.

It means that solve couldn't use the assumption of x and y being real.

On the other hand, reading RealDomain package, y^(1/3) is returned properly:

with(RealDomain):
solve(b,x);
(1/3)
y

What I want to ask you is

Aren't there ways other than using the RealDomain package, to obtain the solution of y^(1/3)?

Best wishes.

taro

## How to parse with certain options? ...

Maple 2015

Hello people in mapleprimes

In the help of parse, there is the following example.

I could not understand why the first one is 4, and next 4^2, and the last 4^3 appeared, there.

Please tell me the way n is increased with the output taking 4, 4^2 and 4^3 sequentially in this example.

n := 0;
n := 0
input := "a := 4; a^2; a^3;";
input := "a := 4; a^2; a^3;"
4
16
64

I know that it is written in the help that lastread shows the next unparsed character,

with the offset the next statement.

taro

## How to find this integral?...

Maple 2015

Hello people in mapleprimes,

I cannot obtain a proper result from the following code.

a:=int(((beta/beta[1,2])^(-theta/(1-theta))-kappa[1]^(-theta/(1-theta)))*m*beta^(m-1),beta=0 .. kappa[1]*beta[1,2]);

Please tell me if you know how to have maple calculate it.

taro

## Procedure of constrained optimum...

Maple 2015

Hello people in mapleprime

maxi:=proc(obj,expre,x,y)
local eq1,eq2,eq3,lagrangean;
lagrangean:=obj+lambda*expre;
eq1:=diff(lagrangean,x)=0:
eq2:=diff(lagrangean,y)=0:
eq3:=diff(lagrangean,lambda)=0:
solve({eq1,eq2,eq3},{x,y});
end proc;

Using the above procedure, next code will not return the values of a and b, or a[2] and b[2].

Can you teach me the reason why?

maxi(a*b,z-a-b,a,b);

maxi(a[2]*b[2],z-a[2]-b[2],a[2],b[2])

taro

## How does evalf@Int choose points?...

Maple 2015

Hello people in mapleprimes,

I have a question about how Int does.

The following function spy returns 0, of course, with a side effect of listing the value of x one by one to secrets.

secrets := NULL:

spy:=proc(x::{name,numeric})
global secrets;
if type(x,name) then
return 'procname'(args)
else
secrets:=x,secrets;
return 0;
end if;
end proc;

And, with this function, calculation of the Int, that is, following brings a sequence of numbers:

evalf(Int(spy,0..1));

secrets;

.7506605773, .2493394227, .9118140517, 0.881859483e-1, .9970470440, 0.29529560e-2, 1.0000000000, 2.2449529449*10^(-11), .5000000000

The question I have is why the number of this sequence is not from smaller( or greater) to greater (smaller) in order,

but in random order. And, numerical calculation of Int can be done with only 9 points extracted?

Best wishes.

taro

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