How can I do with this ntegrand ??

Posted on 2008-05-13 04:56 By liuyaodong (

14)

Categories:

How do I ...? with Maple

R := 0.6e-1*[arctan(10*s/1.3+10*(-.3))/Pi+1/2]

x(s):=Init(sqrt(1-(6*Pi/(1.3)0.06 [R(s)])^(2)-[D(R(s),s)]^(2)),s=0..1.3);

why there is no result ?error?

correct syntax

Comment on 2008-05-13 09:02 from Doug Meade ( Maple Rating 4

739)

There are too many syntax errors in what you posted to list them all. The misspelling of Int is only the start. The general problems are that square brackets cannot be used as parentheses, multiplication should not be implied (i.e., use *), and you have to decide to use an expression or a function.

When I fix all of these, here's what I get:

R :=  s -> 0.6e-1*(arctan(10*s/1.3+10*(-.3))/Pi+1/2);
          /      /10 s            \    \
          |arctan|---- + (-10) 0.3|    |
          |      \1.3             /   1|
s -> 0.06 |------------------------ + -|
          \           Pi              2/
x:=Int(sqrt(1-(6*Pi/(1.3)*0.06 (R(s)))^(2)-(D(R)(s))^(2)),s=0..1.3);
   /1.3                                                                    
  |                                                                (1/2)   
  |     /                    2             0.2130177514           \        
  |     |1 - 0.07668639050 Pi  - ---------------------------------|      ds
  |     |                                                    2    |        
 /0     |                        /                         2\    2|        
        \                        \1 + (7.692307692 s - 3.0) /  Pi /        
value( x );
                                0.6365144807

Doug

---------------------------------------------------------------------
Douglas B. Meade  <><
Math, USC, Columbia, SC 29208  E-mail: mailto:meade@math.sc.edu       
Phone:  (803) 777-6183         URL:    http://www.math.sc.ed

Thank you!, Doug Meade

Comment on 2008-05-13 21:40 from liuyaodong (

14)

Dear Doug,

I am a newer with Maple ,so I have too many things that I don't know. Thank you for helping me,Doug Meade.With your help ,I think I can solve my trouble.Thank you again!

liu

I find something not to understand,can you tell me why?

Comment on 2008-06-24 03:36 from liuyaodong (

14)

Dear Doug,

I find something not to understand,you said that

"x:=Int(sqrt(1-(6*Pi/(1.3)*0.06 (R(s)))^(2)-(D(R)(s))^(2)),s=0..1.3);

          /1.3
         |                                                                                             (1/2)
         |     /                                      2         0.2130177514               \
         |     |1 - 0.07668639050 Pi - ---------------------------------    |      ds
         |     |                                                                                  2       |
         /0   |                        /                                                     2\       2|
                \                        \1 + (7.692307692 s - 3.0)         / Pi    /
value( x );
                                0.6365144807                                                              "

but I also write" x:=Int(sqrt(1-(6*Pi/(1.3)*0.06 (R(s)))^(2)-(D(R)(s))^(2)),s=0..1.3);" and get the result as following.

> x := Int(sqrt(1-((6*Pi/(1.3)*0.6e-1)*R(s))^2-(D(R))(s)^2), s = 0 .. 1.3);
   /1.3
|     /
|     |
|     |1
|     |
/0     |
        \

                                                                                                                                        2
                                       2 /0.06 arctan(7.692307692 s - 3.0)                                \
    - 0.07668639052 Pi |-------------------------------- -------------+ 0.03000000000|
                                         \               Pi                                                                        /

                                                                                  \
                0.2130177514                                       |
    - ------------------------------------------------            | ^(1/2) ds
                                                         2                       |
      /                                             2 \    2                   |
      \1 + (7.692307692 s - 3.0) / Pi                      /
> value(x);
                                   1.296827065

can you tell me why,and it is very important for me!

Thank you !

Liu

Another error

Comment on 2008-06-24 13:49 from Robert Israel ( Maple Rating 4

1555)

Doug neglected to correct one more error: he didn't have a multiplication sign * after the 0.06. Unfortunately this is one of the cases where 1D input (which I suspect Doug was using) and 2D input (which I suspect you are using) act differently, as was discussed here a number of times.