Problem in derivative of big eqaution in mathematica

[funyhony]

i want to put this equation in mathematica to have derivative


i always have error

please tell me how to write it in mathematica to get the derivative

also to solve the equation

i attache the equation in word file

 

[funyhony]

attached file here

 

[Bill Simpson]

This is not a complete solution to your problem, but perhaps this will get you started:

J = Sum[Subscript[y, m]Log[Subscript[P, m]] +
(1 - Subscript[y, m])Log[1 - Subscript[P, m]], {m, 1, M}]-
\[Lambda]/K Sum[Sum[(Subscript[P, m]Subscript[P, mPrime])^2,
{mPrime, unknown, unknown}], {m, 1, M + CapN}];
Solve[D[J, Subscript[P, m]] == 0, Subscript[P, m]]

You have to provide more information or figure out on your own whether K is a constant in one place and a function on mPrime in another or somehow find a way to bring your idea of summing over selected elements of a set in line with Mathematica's idea of Sum working with an index variable over a sequential list of integral values. Adjust that inner Sum[] and {mPrime, unknown, unknown} accordingly. It is possible to toss out Sum and use other methods, but I'm guessing from your question that you might not be up to figuring that out.

One other polite comment. I do realize that many people have come to believe that they must, or at least should be able to, "desktop publish" everything they do, inside and outside Mathematica, including subscripts, superscripts, primes, choosing case that matches the notation from a paper or personal choice, etc. In my experience that usually seems to make the task about twice as hard to do. Maybe you will have better luck. You may find in a variety of ways and places in Mathematica that support for this is uneven and mixed and difficult to diagnose when something doesn't work as expected, above and beyond the usual level of Mathematica being cranky and difficult to diagnose why something isn't working. I hope it works out for you.

 

[funyhony]

Dear Bill
i really thank you for your help i really learned from you i couldn't know how to write m' and the sum , i was writing them as in word equation

i still have problem in the part of summition m' k(xm)

i don't know how to put the unknown values
i'll try again and tell you what happened

i've more complicated equation with Pmi and m is rows and i is columns from a data base, i mean Pmi have many variations
can this equation be derived and solved with mathematica to get Pmi equation

i really approciate your help so much
thanks so much :)

 

[alphy]

I understand your frustration with encountering errors while trying to input a complex equation into Mathematica. It is important to ensure that the equation is written correctly and in the appropriate format for Mathematica to understand and perform the desired operations.

To input an equation into Mathematica and obtain its derivative, you can use the built-in function "D". For example, if your equation is written as "f(x) = x^2 + 3x + 5", you can use the command "D[f[x],x]" to obtain the derivative of f(x) with respect to x.

If you are still encountering errors, it may be helpful to consult the Mathematica documentation or seek assistance from other Mathematica users. Additionally, there are various online resources and forums where you can find tips and solutions for specific issues in Mathematica.

Regarding solving the equation, Mathematica has a built-in function "Solve" that can be used to find solutions to equations. However, the equation must be written in a specific format for Mathematica to solve it. Again, checking the documentation or seeking assistance from others may be helpful in this process.

I hope this helps you in successfully inputting and obtaining derivatives and solutions for your equations in Mathematica. Remember to always double-check your equation and its format to avoid errors. Best of luck in your research.