MathGroup Archive 1998

[Date Index] [Thread Index] [Author Index]

Search the Archive

Please Help !!! - Problem in Plot



I am to solve the following formula ;

soln1=Solve[x*(1-x)^(z-2)==y*(1-y)^(z-2), x]

where z = 6, and it is expected that x is the function of y.

and got the following six solutions ;

Out[]=
  ({{x -> y}, {
      x ->
        (4 - y)/4 -
          1/2[Sqrt]((
                ( - 6) + 1/4(((-4) + y))^2 + 4 y - y^2 + 1/3((6 - 4 y +
y^2)) +
                  ((2*2^(1/3)(((-1) + y))^2 y(((-6) + 5 y)
                        )))/((3(((-45) y^2 + 160\ y\^3 - 210\ y\^4 +
                              120\ y\^5 - 25\ y\^6 +
                              \[Sqrt]\((
                                  6912\ y\^3 - 56727\ y\^4 + 207360\
y\^5 -
                                    443340\ y\^6 + 611280\ y\^7 -
                                    563922\ y\^8 + 348192\ y\^9 -
                                    138780\ y\^10 + 32400\ y\^11 -
                                    3375\ y\^12)\))\)^\((1/3)\))\) +
                  \(1\/\(3\ 2\^\(1/3\)\)\((
                    \((\(-45\)\ y\^2 + 160\ y\^3 - 210\ y\^4 + 120\ y\^5
-
                          25\ y\^6 +
                          \[Sqrt]\((
                              6912\ y\^3 - 56727\ y\^4 + 207360\ y\^5 -
                                443340\ y\^6 + 611280\ y\^7 - 563922\
y\^8 +
                                348192\ y\^9 - 138780\ y\^10 + 32400\
y\^11 -
                                3375\ y\^12)\))\)^\((1/3)\))\)\))\) -
          1\/2\ \[Sqrt]\((
                \( - 6\) + 1\/2\ \((\(-4\) + y)\)\^2 + 4\ y - y\^2 +
                  1\/3\ \((\(-6\) + 4\ y - y\^2)\) -
                  \((2\ 2\^\(1/3\)\ \((\(-1\) + y)\)\^2\ y\ \((\(-6\) +
5\ y)
                        \))\)/\((
                      3\ \((\(-45\)\ y\^2 + 160\ y\^3 - 210\ y\^4 +
                              120\ y\^5 - 25\ y\^6 +
                              \[Sqrt]\((
                                  6912\ y\^3 - 56727\ y\^4 + 207360\
y\^5 -
                                    443340\ y\^6 + 611280\ y\^7 -
                                    563922\ y\^8 + 348192\ y\^9 -
                                    138780\ y\^10 + 32400\ y\^11 -
                                    3375\ y\^12)\))\)^\((1/3)\))\) -
                  \(1\/\(3\ 2\^\(1/3\)\)\((
                    \((\(-45\)\ y\^2 + 160\ y\^3 - 210\ y\^4 + 120\ y\^5
-
                          25\ y\^6 +
                          \[Sqrt]\((
                              6912\ y\^3 - 56727\ y\^4 + 207360\ y\^5 -
                                443340\ y\^6 + 611280\ y\^7 - 563922\
y\^8 +
                                348192\ y\^9 - 138780\ y\^10 + 32400\
y\^11 -
                                3375\ y\^12)\))\)^\((1/3)\))\)\) -
                  \((\(-\((\(-4\) + y)\)\^3\) +
                        4\ \((\(-4\) + y)\)\ \((6 - 4\ y + y\^2)\) -
                        8\ \((\(-4\) + 6\ y - 4\ y\^2 + y\^3)\))\)/
                    \((4\ \[Sqrt]\((
                            \( - 6\) + 1\/4\ \((\(-4\) + y)\)\^2 + 4\ y
-
                              y\^2 + 1\/3\ \((6 - 4\ y + y\^2)\) +
                              \((2\ 2\^\(1/3\)\ \((\(-1\) + y)\)\^2\ y\
\((
                                    \(-6\) + 5\ y)\))\)/
                                \((3\ \((
                                        \(-45\)\ y\^2 + 160\ y\^3 -
                                        210\ y\^4 + 120\ y\^5 - 25\ y\^6
+
                                        \[Sqrt]\((
                                        6912\ y\^3 - 56727\ y\^4 +
                                        207360\ y\^5 - 443340\ y\^6 +
                                        611280\ y\^7 - 563922\ y\^8 +
                                        348192\ y\^9 - 138780\ y\^10 +
                                        32400\ y\^11 - 3375\
y\^12)\))\)^
                                      \((1/3)\))\) +
                              \(1\/\(3\ 2\^\(1/3\)\)\((
                                \((\(-45\)\ y\^2 + 160\ y\^3 - 210\ y\^4
+
                                      120\ y\^5 - 25\ y\^6 +
                                      \[Sqrt]\((
                                        6912\ y\^3 - 56727\ y\^4 +
                                        207360\ y\^5 - 443340\ y\^6 +
                                        611280\ y\^7 - 563922\ y\^8 +
                                        348192\ y\^9 - 138780\ y\^10 +
                                        32400\ y\^11 - 3375\
y\^12)\))\)^
                                  \((1/3)\))\)\))\))\))\)}, {
      x ->
        (4 - y)/4 -
          1\/2\ \[Sqrt]\((
                \( - 6\) + 1\/4\ \((\(-4\) + y)\)\^2 + 4\ y - y\^2 +
                  1\/3\ \((6 - 4\ y + y\^2)\) +
                  \((2\ 2\^\(1/3\)\ \((\(-1\) + y)\)\^2\ y\ \((\(-6\) +
5\ y)
                        \))\)/\((
                      3\ \((\(-45\)\ y\^2 + 160\ y\^3 - 210\ y\^4 +
                              120\ y\^5 - 25\ y\^6 +
                              \[Sqrt]\((
                                  6912\ y\^3 - 56727\ y\^4 + 207360\
y\^5 -
                                    443340\ y\^6 + 611280\ y\^7 -
                                    563922\ y\^8 + 348192\ y\^9 -
                                    138780\ y\^10 + 32400\ y\^11 -
                                    3375\ y\^12)\))\)^\((1/3)\))\) +
                  \(1\/\(3\ 2\^\(1/3\)\)\((
                    \((\(-45\)\ y\^2 + 160\ y\^3 - 210\ y\^4 + 120\ y\^5
-
                          25\ y\^6 +
                          \[Sqrt]\((
                              6912\ y\^3 - 56727\ y\^4 + 207360\ y\^5 -
                                443340\ y\^6 + 611280\ y\^7 - 563922\
y\^8 +
                                348192\ y\^9 - 138780\ y\^10 + 32400\
y\^11 -
                                3375\ y\^12)\))\)^\((1/3)\))\)\))\) +
          1\/2\ \[Sqrt]\((
                \( - 6\) + 1\/2\ \((\(-4\) + y)\)\^2 + 4\ y - y\^2 +
                  1\/3\ \((\(-6\) + 4\ y - y\^2)\) -
                  \((2\ 2\^\(1/3\)\ \((\(-1\) + y)\)\^2\ y\ \((\(-6\) +
5\ y)
                        \))\)/\((
                      3\ \((\(-45\)\ y\^2 + 160\ y\^3 - 210\ y\^4 +
                              120\ y\^5 - 25\ y\^6 +
                              \[Sqrt]\((
                                  6912\ y\^3 - 56727\ y\^4 + 207360\
y\^5 -
                                    443340\ y\^6 + 611280\ y\^7 -
                                    563922\ y\^8 + 348192\ y\^9 -
                                    138780\ y\^10 + 32400\ y\^11 -
                                    3375\ y\^12)\))\)^\((1/3)\))\) -
                  \(1\/\(3\ 2\^\(1/3\)\)\((
                    \((\(-45\)\ y\^2 + 160\ y\^3 - 210\ y\^4 + 120\ y\^5
-
                          25\ y\^6 +
                          \[Sqrt]\((
                              6912\ y\^3 - 56727\ y\^4 + 207360\ y\^5 -
                                443340\ y\^6 + 611280\ y\^7 - 563922\
y\^8 +
                                348192\ y\^9 - 138780\ y\^10 + 32400\
y\^11 -
                                3375\ y\^12)\))\)^\((1/3)\))\)\) -
                  \((\(-\((\(-4\) + y)\)\^3\) +
                        4\ \((\(-4\) + y)\)\ \((6 - 4\ y + y\^2)\) -
                        8\ \((\(-4\) + 6\ y - 4\ y\^2 + y\^3)\))\)/
                    \((4\ \[Sqrt]\((
                            \( - 6\) + 1\/4\ \((\(-4\) + y)\)\^2 + 4\ y
-
                              y\^2 + 1\/3\ \((6 - 4\ y + y\^2)\) +
                              \((2\ 2\^\(1/3\)\ \((\(-1\) + y)\)\^2\ y\
\((
                                    \(-6\) + 5\ y)\))\)/
                                \((3\ \((
                                        \(-45\)\ y\^2 + 160\ y\^3 -
                                        210\ y\^4 + 120\ y\^5 - 25\ y\^6
+
                                        \[Sqrt]\((
                                        6912\ y\^3 - 56727\ y\^4 +
                                        207360\ y\^5 - 443340\ y\^6 +
                                        611280\ y\^7 - 563922\ y\^8 +
                                        348192\ y\^9 - 138780\ y\^10 +
                                        32400\ y\^11 - 3375\
y\^12)\))\)^
                                      \((1/3)\))\) +
                              \(1\/\(3\ 2\^\(1/3\)\)\((
                                \((\(-45\)\ y\^2 + 160\ y\^3 - 210\ y\^4
+
                                      120\ y\^5 - 25\ y\^6 +
                                      \[Sqrt]\((
                                        6912\ y\^3 - 56727\ y\^4 +
                                        207360\ y\^5 - 443340\ y\^6 +
                                        611280\ y\^7 - 563922\ y\^8 +
                                        348192\ y\^9 - 138780\ y\^10 +
                                        32400\ y\^11 - 3375\
y\^12)\))\)^
                                  \((1/3)\))\)\))\))\))\)}, {
      x ->
        (4 - y\)\/4 +
          1\/2\ \[Sqrt]\((
                \( - 6\) + 1\/4\ \((\(-4\) + y)\)\^2 + 4\ y - y\^2 +
                  1\/3\ \((6 - 4\ y + y\^2)\) +
                  \((2\ 2\^\(1/3\)\ \((\(-1\) + y)\)\^2\ y\ \((\(-6\) +
5\ y)
                        \))\)/\((
                      3\ \((\(-45\)\ y\^2 + 160\ y\^3 - 210\ y\^4 +
                              120\ y\^5 - 25\ y\^6 +
                              \[Sqrt]\((
                                  6912\ y\^3 - 56727\ y\^4 + 207360\
y\^5 -
                                    443340\ y\^6 + 611280\ y\^7 -
                                    563922\ y\^8 + 348192\ y\^9 -
                                    138780\ y\^10 + 32400\ y\^11 -
                                    3375\ y\^12)\))\)^\((1/3)\))\) +
                  \(1\/\(3\ 2\^\(1/3\)\)\((
                    \((\(-45\)\ y\^2 + 160\ y\^3 - 210\ y\^4 + 120\ y\^5
-
                          25\ y\^6 +
                          \[Sqrt]\((
                              6912\ y\^3 - 56727\ y\^4 + 207360\ y\^5 -
                                443340\ y\^6 + 611280\ y\^7 - 563922\
y\^8 +
                                348192\ y\^9 - 138780\ y\^10 + 32400\
y\^11 -
                                3375\ y\^12)\))\)^\((1/3)\))\)\))\) -
          1\/2\ \[Sqrt]\((
                \( - 6\) + 1\/2\ \((\(-4\) + y)\)\^2 + 4\ y - y\^2 +
                  1\/3\ \((\(-6\) + 4\ y - y\^2)\) -
                  \((2\ 2\^\(1/3\)\ \((\(-1\) + y)\)\^2\ y\ \((\(-6\) +
5\ y)
                        \))\)/\((
                      3\ \((\(-45\)\ y\^2 + 160\ y\^3 - 210\ y\^4 +
                              120\ y\^5 - 25\ y\^6 +
                              \[Sqrt]\((
                                  6912\ y\^3 - 56727\ y\^4 + 207360\
y\^5 -
                                    443340\ y\^6 + 611280\ y\^7 -
                                    563922\ y\^8 + 348192\ y\^9 -
                                    138780\ y\^10 + 32400\ y\^11 -
                                    3375\ y\^12)\))\)^\((1/3)\))\) -
                  \(1\/\(3\ 2\^\(1/3\)\)\((
                    \((\(-45\)\ y\^2 + 160\ y\^3 - 210\ y\^4 + 120\ y\^5
-
                          25\ y\^6 +
                          \[Sqrt]\((
                              6912\ y\^3 - 56727\ y\^4 + 207360\ y\^5 -
                                443340\ y\^6 + 611280\ y\^7 - 563922\
y\^8 +
                                348192\ y\^9 - 138780\ y\^10 + 32400\
y\^11 -
                                3375\ y\^12)\))\)^\((1/3)\))\)\) +
                  \((\(-\((\(-4\) + y)\)\^3\) +
                        4\ \((\(-4\) + y)\)\ \((6 - 4\ y + y\^2)\) -
                        8\ \((\(-4\) + 6\ y - 4\ y\^2 + y\^3)\))\)/
                    \((4\ \[Sqrt]\((
                            \( - 6\) + 1\/4\ \((\(-4\) + y)\)\^2 + 4\ y
-
                              y\^2 + 1\/3\ \((6 - 4\ y + y\^2)\) +
                              \((2\ 2\^\(1/3\)\ \((\(-1\) + y)\)\^2\ y\
\((
                                    \(-6\) + 5\ y)\))\)/
                                \((3\ \((
                                        \(-45\)\ y\^2 + 160\ y\^3 -
                                        210\ y\^4 + 120\ y\^5 - 25\ y\^6
+
                                        \[Sqrt]\((
                                        6912\ y\^3 - 56727\ y\^4 +
                                        207360\ y\^5 - 443340\ y\^6 +
                                        611280\ y\^7 - 563922\ y\^8 +
                                        348192\ y\^9 - 138780\ y\^10 +
                                        32400\ y\^11 - 3375\
y\^12)\))\)^
                                      \((1/3)\))\) +
                              \(1\/\(3\ 2\^\(1/3\)\)\((
                                \((\(-45\)\ y\^2 + 160\ y\^3 - 210\ y\^4
+
                                      120\ y\^5 - 25\ y\^6 +
                                      \[Sqrt]\((
                                        6912\ y\^3 - 56727\ y\^4 +
                                        207360\ y\^5 - 443340\ y\^6 +
                                        611280\ y\^7 - 563922\ y\^8 +
                                        348192\ y\^9 - 138780\ y\^10 +
                                        32400\ y\^11 - 3375\
y\^12)\))\)^
                                  \((1/3)\))\)\))\))\))\)}, {
      x ->
       (4 - y\)\/4 +
          1\/2\ \[Sqrt]\((
                \( - 6\) + 1\/4\ \((\(-4\) + y)\)\^2 + 4\ y - y\^2 +
                  1\/3\ \((6 - 4\ y + y\^2)\) +
                  \((2\ 2\^\(1/3\)\ \((\(-1\) + y)\)\^2\ y\ \((\(-6\) +
5\ y)
                        \))\)/\((
                      3\ \((\(-45\)\ y\^2 + 160\ y\^3 - 210\ y\^4 +
                              120\ y\^5 - 25\ y\^6 +
                              \[Sqrt]\((
                                  6912\ y\^3 - 56727\ y\^4 + 207360\
y\^5 -
                                    443340\ y\^6 + 611280\ y\^7 -
                                    563922\ y\^8 + 348192\ y\^9 -
                                    138780\ y\^10 + 32400\ y\^11 -
                                    3375\ y\^12)\))\)^\((1/3)\))\) +
                  \(1\/\(3\ 2\^\(1/3\)\)\((
                    \((\(-45\)\ y\^2 + 160\ y\^3 - 210\ y\^4 + 120\ y\^5
-
                          25\ y\^6 +
                          \[Sqrt]\((
                              6912\ y\^3 - 56727\ y\^4 + 207360\ y\^5 -
                                443340\ y\^6 + 611280\ y\^7 - 563922\
y\^8 +
                                348192\ y\^9 - 138780\ y\^10 + 32400\
y\^11 -
                                3375\ y\^12)\))\)^\((1/3)\))\)\))\) +
          1\/2\ \[Sqrt]\((
                \( - 6\) + 1\/2\ \((\(-4\) + y)\)\^2 + 4\ y - y\^2 +
                  1\/3\ \((\(-6\) + 4\ y - y\^2)\) -
                  \((2\ 2\^\(1/3\)\ \((\(-1\) + y)\)\^2\ y\ \((\(-6\) +
5\ y)
                        \))\)/
                    \((3\ \((
                            \(-45\)\ y\^2 + 160\ y\^3 - 210\ y\^4 +
                              120\ y\^5 - 25\ y\^6 +
                              \[Sqrt]\((
                                  6912\ y\^3 - 56727\ y\^4 + 207360\
y\^5 -
                                    443340\ y\^6 + 611280\ y\^7 -
                                    563922\ y\^8 + 348192\ y\^9 -
                                    138780\ y\^10 + 32400\ y\^11 -
                                    3375\ y\^12)\))\)^\((1/3)\))\) -
                  \(1\/\(3\ 2\^\(1/3\)\)\((
                    \((\(-45\)\ y\^2 + 160\ y\^3 - 210\ y\^4 + 120\ y\^5
-
                          25\ y\^6 +
                          \[Sqrt]\((
                              6912\ y\^3 - 56727\ y\^4 + 207360\ y\^5 -
                                443340\ y\^6 + 611280\ y\^7 - 563922\
y\^8 +
                                348192\ y\^9 - 138780\ y\^10 + 32400\
y\^11 -
                                3375\ y\^12)\))\)^\((1/3)\))\)\) +
                  \((\(-\((\(-4\) + y)\)\^3\) +
                        4\ \((\(-4\) + y)\)\ \((6 - 4\ y + y\^2)\) -
                        8\ \((\(-4\) + 6\ y - 4\ y\^2 + y\^3)\))\)/
                    \((4\ \[Sqrt]\((
                            \( - 6\) + 1\/4\ \((\(-4\) + y)\)\^2 + 4\ y
-
                              y\^2 + 1\/3\ \((6 - 4\ y + y\^2)\) +
                              \((2\ 2\^\(1/3\)\ \((\(-1\) + y)\)\^2\ y\
\((
                                    \(-6\) + 5\ y)\))\)/
                                \((3\ \((
                                        \(-45\)\ y\^2 + 160\ y\^3 -
                                        210\ y\^4 + 120\ y\^5 - 25\ y\^6
+
                                        \[Sqrt]\((
                                        6912\ y\^3 - 56727\ y\^4 +
                                        207360\ y\^5 - 443340\ y\^6 +
                                        611280\ y\^7 - 563922\ y\^8 +
                                        348192\ y\^9 - 138780\ y\^10 +
                                        32400\ y\^11 - 3375\
y\^12)\))\)^
                                      \((1/3)\))\) +
                              \(1\/\(3\ 2\^\(1/3\)\)\((
                                \((\(-45\)\ y\^2 + 160\ y\^3 - 210\ y\^4
+
                                      120\ y\^5 - 25\ y\^6 +
                                      \[Sqrt]\((
                                        6912\ y\^3 - 56727\ y\^4 +
                                        207360\ y\^5 - 443340\ y\^6 +
                                        611280\ y\^7 - 563922\ y\^8 +
                                        348192\ y\^9 - 138780\ y\^10 +
                                        32400\ y\^11 - 3375\
y\^12)\))\)^
                                  \((1/3)\))\)\))\))\))\)}}\)

I make the pure function R[x], later it should be used in another
expression, as follows;

R[x_]:=soln1[[2]] /.y->x

Problem occurred when I plot this function

Plot[R[x], {x,0,1}]

Mathematica displays following messages ;

Plot::plnr:
    "R[x] is not a machine-size real number at x =
4.16666666666666607`*^-8
Plot::plnr:
    R[x] is not a machine-size real number at x = 0.0405669915729157892
Plot::plnr:
    R[x] is not a machine-size real number at x = 0.0848087998593736713
General::stop:
    Further output of (Plot :: plnr) will be suppressed during this
calculation.

and in  Front End Message is as follows

******************************************************************************

Front End Message
The string '\!\(R[x]\) is not a machine-size real number at x =
4.16666666666666607`*^-8' cannot be displayed with
ShowStringCharacters->False  due to an error in the string.
******************************************************************************

However, when these values are put into R[x]

In[1]:=r[4.16666666666666607`*^-8]
Out[1]={x -> 0.985661}
In[2]:=r[0.0405669915729157892]
Out[2]={x -> 0.4836810121606896}
In[3]:=r[0.0848087998593736713]
Out[3]={x ->0.3642868596845246}

What is the meaning of above Front End Message ? What is wrong?

Please help me !!!!

Thanks for reading.








  • Prev by Date: Re: Eigenvalues
  • Next by Date: help
  • Prev by thread: Mathematica 3.0: How to change thickness of 3D-curve (ParametricPlot3D)
  • Next by thread: help