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)?

I will be very glad if you give me answers.

Best wishes.

taro

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;"
parse(input,'lastread'='n','offset'=n,statement);
                               4
parse(input,'lastread'='n','offset'=n,statement);
                               16
parse(input,'lastread'='n','offset'=n,statement);
                               64

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

with the offset the next statement.

Thanks in advance

taro

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.

Thanks in advance.

taro

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])

Thanks in advance.

taro

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