## 698 Reputation

15 years, 95 days

## I found a new way...

add(numbcomb(80, x)*numbcomb(100, 27-x), x = 1 .. 27)

## maybe,,,I should choose the...

maybe,,,I should choose the font manually,

but how to make the font in 2D-math become Time New Roman by defaut、

question2:

-***-

the second " minus sign " is too short compared with the first one in 2D-Math mode.

## Thanks,How to solve for...

Thanks,How to solve for other points?

{a -> 1/2, b -> 7/16, c -> Sqrt[143]/16}}

the mimimun value of the function is also 2sqrt(3)

In this example,how to solve for it by Lagrange Multiplier method.

I've tried some ways in Mathematica,Plot3D,and solve some related equations are so Time-consuming!

## In this sample,I use...

In this sample,I use ImageMultiply[,1.3] in mathematica to get a acceptable picture.

how to get the parameter 1.3 easily? I've tried it for several times.

And how to make it more clear?

## question2:Can I use...

question2:

Can I use CrossRatio to solve for the transformation?

for example:the one make 0,i,-i become 1,-1,0

f := proc (z) options operator, arrow; (a*z+b)/(c*z+d) end proc

> solve({f(0) = 1, f(-I) = 0, f(I) = -1}, {a, b, c});
{a = -I d, b = d, c = 3 I d}
> subs(%, f(z));
-I d z + d
-----------
3 I d z + d
> simplify(%);

question3: add simplify(%) to last expresion as a option.

such like //Simplify in Mma

question4:

Use p=(z1,z2,z3,z4) to express values of different permutations of cross ratio (z1,z2,z3,z4)

## all right,used to use...

all right,

used to use diff

can diff take effect in a number? like D(4)=0？ And use D to do this:diff(x, x)=1

question2:

any other commands to do eigenvalues?

> with(LinearAlgebra);
> Eigenvalues(B);

a little long...

## I don't know why,No matter...

I don't know why,No matter how I adjust the second and third pictures,they all look the same ,and so strange..

## Robert, Can you see...

Robert, Can you see the pictures in question 3?

The Disk without a small area,this can also be plotted in mathematica by using RegionPlot.

But I don't know how to add the  stripes on it like that plotted by using confomal

## question2:convert ...

question2:convert  -I*(-1+z)/(1+z) to (I-I*z)/(1+z)

Maybe I'd asked the problem,but I forget it.

question3:Plot this:

ParametricPlot[{r Cos[\[Theta]], r Sin[\[Theta]]}, {\[Theta], 0,
2 Pi}, {r, 0, 2}]

The circles should not be equidistant

## Error, recursive...

sometimes it comes out error information

Error, recursive assignment
...

I don't no why now come out error,,,

Ok,If I use capital letter X,it's ok.

## How to transpose the data in...

question2:How to transpose the data in Excel with Maple?

question 3:Do you know how to delete the even line in Excel itself?

question 4:

b := FileTools[ListDirectory]("E:/New Folder")

then b will contain the document folders and "Thumbs.db",

Can maple filter some specific files?,for example show only .jpg pictures' name

or other methods to get oldnames?

my next goal is to make maple omit the names already exist in the folder.

## ? why my reply- four was...

([seq])(readline("word.txt", datatype = string), i = 1 .. 10, 2)

why the step is not as the description in Help?

for the step is 2,then will read the five line,not the line 1,3,5,7...

## oh,thanks, for the...

oh,thanks,

for the results,this is ok,

can we make the process more written? demonstrate the process.

## question2:subset !=...

question2:

subset != ⊆  ???

with command completion

subset = ⊂ it's different from the appearance in palette.

sub = ⊂ this is enough,subset should be ⊆,though SubsetEqual is also equal ⊆

question 3:

Is this a bug?

In text mode,

Type a word,like this  "suppose" then click the click ϕ int the greek letter palette,the inputted was φ,when click φ,the inputted was  ϕ

but the actual inputted was right,when copy the φ here or to a new document,it become ϕ,

Is that the same in your computers?

question 4:

how to input overline easily ,OverBarOver no command completion ?

conjugate is that?

## use Mma is also ok,but I...

use Mma is also ok,but I don't know how to do

FileNames[]

{"10.jpg", "11.jpg", "1.jpg", "2.jpg", "3.jpg", "4.jpg", "5.jpg", \
"6.jpg", "7.jpg", "8.jpg", "9.jpg"}

but the names' sort in the list is strange,the eleven pictures are sort by the size correspoinding to its name,date modified.

b = Import["word.txt", "Lines"]

p = FileNames[]

For[i = 1, i <= 11, i++, RenameFile[p[[i]], b[[i]]]]

It's ok

but I should to perfect it.