# Items tagged with functionfunction Tagged Items Feed

### How to convert into elementary functions?...

July 08 2015
2 11

Maple is providing answers with the gamma function and LambertW function.  I am not a math major.  Although I did take advanced engineering mathematics in grad school, I am not familiar with transcendental functions.

I did look at some of the help.  I tried to use the convert command to convert to elementary functions, however it did not help.  I looked at the definition for the Gamma function, GAMMA(z), and the upper incomplete Gamma function, GAMMA(a,z) that uses the generalized hypergeometric function 1F1.  Looking at the generalized hypergeometric function 1F1 defintion, hypergeom(n, d, z), it references the general pochhammer function, pochhammer(z, a), and product functions, product(f,k=m..n).  This all seems way too complicated.

eqn1:= R = exp(t/MTBF) * (t/MTBF) * sum(1/(i!), i=0..n);

eqn2:= MTBF = solve(eqn1,MTBF);

Is there any easy way to convert to use basic functions like sum, int, etc.??

I am wanting to use the answer in Excel.  I have found some custom Excel VBA code that I could use to implement these non-standard function in Excel, but that seems like a lot of effort.

Excel Add-Ins Incomplete Gamma Function (PC Review)

Update: Some more background on the problem is as follows. R is the expected reliability say 90%. MTBF is mean time between failures in hours. t is the time period of operation excluding allowable downtime. n is the allowed number of failures. I am looking to find the MTBF needed to achieve a certain required reliability, with the number of failures allowed, and the up-time operational period, being defined by the requirements as well.

To clarify the simplification does not necessarily have to be closed form, and an approximation would be acceptable. (in Excel I currently am using iteration over a number of rows, then using the Goal Seek tool to find the MTBF, however this is less than desirable to have to do everytime when looking at different trade studies) I am not that familiar with how to use assumptions in Maple, and do not know what would be the appropriate assumptions to make when simplifying. Thanks for your help.

### Set Uneval globally/ Simplification with unspecifi...

June 25 2015
1 5

Hello, i got the following problem. I have a function, say u(h,e) whith multiple exponents . As long as Maple does not know that u(h,e) is positiv it won't make the simplification and return u(h,e) as expected. From my view i have two possibilites to solve this problem:

1) Define u(h,e) to be positive. Sounds intuitive, but i didn't manage to find the right definition

2) Give maple the function e.g. u:=e+h^2 and simplify the epression in uneval quotes with assumption positive for e and h.

Whereas I have solution 2, the problem is that i would need excessive amounts of uneval quotes '' at the start of my worksheet, not to run out of them.

I definitly need my epressions in unevaluated forms and would be happy to hear any ideas.

Greetings, Fabian

### calculate values function.......

June 24 2015
0 7

Hi every body:

I have a problem with below function (f(x)), I will calculate values this function with for loop so that values are closer together. for example I will earn 10 or 20 data for this function so that they differences have to be fixed.my means is that I have 10 data like, 50,65,85,90,100,... no 50,100,170,... . that isn't important for me the data increase with constant value but my final data must be closer together. (the maximum number of my data to be taken is 50).

function is:

f:=(x)->(310*(z+0.5)^0.2)+70

z=[-0.5,0.5]

with regards...

Mehran.

### approximation by piece-wise constant function ...

June 23 2015
0 2

Hi

I am trying to approximate a function in terms of piece-wise constant function:

$$f(x) = \sum_0^N c_iB_i(x)$$

what modules/packages of maple are helpful here? thanks

### Error in integration when using an exponential....

May 28 2015
0 1

I am trying to integrate product of exp(t+s) and a piecewise polynomial but the result can not be read and not usefull. also I used numerical integration function "Quadrature" but the result did not change.

### Asymptotic behaviour...

May 21 2015
1 2

How to find asymptotic behaviour of a function.

For example at infinity

sinh(x) behaves as 1/2*exp(x)

1/sinh(x)  behaves as 2*exp(-x)

exp(-x)*(exp(-x)+1) behaves as exp(-x)

so that it works with a more complex expression.

### I forgot how to turn D or diff into a function......

May 14 2015
0 2

I googled everywhere for this and most results just tell me what diff and D does...

Basically I have a function, let's say

f:= x -> x^2

How do I turn the derivative of f into a function?

I tried

fprime := x -> diff(x^2,x)

But tihs just shows me diff(x^2,x), instead of x -> 2x

### Extending a Program(Function)...

May 10 2015
0 3

Hi all

Assume that we have following special matrix(Namely ATilde) for arbitrary vectore  z=[a0,a1,a2,a1*,a2*]:
atild.mws

and we want to use this as a general function for other arbitrary vector. is ther any way?

for example z1=[x,y,t,s,u]?

thanks for any help

best wishes

Ph.D Candidate

Applied Mathematics Department

### How do I check the monotonicity of a function?...

April 20 2015
0 1

This might be a ridiculous question, but what is the easiest way to check the monotonicity of a function? I didn´t find anything helpful in the Maple Help, so maybe one of you could give me a nudge here :)

April 14 2015
2 7

Hello

I am new to Maple, and I would like to get some help. Thank you.

I have an assignment where I had to make a power-regression of some numbers.

Now, I did this. I got this  1,18971*x*0,38480

The next task is to make a prognosis (lol, I don't know how to say that in english), but I had to get to know what x = 17.

Ussualy, you would just put 17 in your function and then calcuate what x=17 is.

Now, I want to know if there's a method in maple where you can solve what x=17 is.

The reason i ask is because our assignment is a "Maple-assignment" so if there's a solve-function, then please let me know.

### plot a function inside a circle...

April 08 2015
1 15

Dear all,

I want to plot for example cos(theta) from 0 to 2*Pi inside a circle at a radius R. The axis theta of the ploted function is at a radius R.

Is it possible ?

Thanks

### Problem with integration....

April 06 2015
0 11

I am performing the int operation on an experssion but it does not consider constants to be constants. For example, maple is considering this constant namely, f'(-1) or eval(diff(f(x), x), x=-1) as a function and henceforth does not give the desired output. Please tell me how to make eval(diff(f(x), x), x=-1) as a constant function or to say, how to convert any given function in to a constant function.

Thank you for your time and help!

### Cannot make this sum into a function...

March 18 2015
1 3

I have sum representation,

N:=3

I tried evaluating at t = 0 or t = 1, it does nothing when I entered f(0)[2]; it returns

I have a big system, so the loop is necessary for the assignment.

### how to make desired polynomials with sum of the po...

March 09 2015
1 2

hi everyone.how can i write a function or procedure or summation so that i can write down the following polynomial ? i just want to create a set of polynomials which their summation of power ( power of x + power of y ) be less than three or equal to three ? the coefficients priority is not important , for example it is not important that a1 multiplies to x or y , i just want to create this polynomial with some coeeficients. tnx for help

 > restart:
 > a[9]*y^3+x^3*a[8]+x^2*y*a[5]+x*y^2*a[7]+x^2*a[2]+x*y*a[4]+y^2*a[6]+x*a[1]+y*a[3]+a[0];
 (1)
 >

### Multiple Equation solver...

March 08 2015
1 2

Hi,

I am new to Maple and have a problem when solving three equations with three variables. But when  I plug in into solve function then it gives no answer.

eqn1 := 24900 = A*exp(-X*1.293995859*10^22)+A*exp(-Y*1.293995859*10^22)+5852.27;

eqn2 := 6000 = A*exp(-X*1.293995859*10^22)+2422.929937;

eqn3 := 19100 = A*exp(-Y*1.293995859*10^22)+8275.199937;

Variables are [A,X,Y]

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