## 571 Reputation

16 years, 57 days
Technical professional in industry or government
Budapest, Hungary

## MaplePrimes Activity

### These are questions asked by djc

Maple

I have found this free library for Maple. It has got a lot of new or improved commands.

## converting tan(z) to sum form with assum...

Maple

Hi,

I am trying to convert tan(z) to sum form using the convert(...,Sum) command and using some information from FunctionAdvisor.
The second operand of FunctionAdvisor( sum_form, tan) gives me the domain of validity.
I would like to use this info during the conversion as assumption, but it doesn't work for me.
(Of course, the first operand is the required sum form, I am just playing with maple).
Here is my problem:

## Problem with singular()...

Maple
In this case there is a singularity at t=0, but the command singular() does not give it: singular(1/cos(1/t)); {t = 2/(Pi*(1+2*_Z1))} With the numeric range option it gives the correct answer: singular(1/cos(1/t), -1 .. 1); {t = 0}, {t = -2/(39*Pi)}, {t = -2/(37*Pi)}, {t = -2/(35*Pi)} etc. The command discont also gives the correct answer: discont(1/cos(1/t),t); {0, 2/(Pi*(1+2*_Z2))} I have maple 11.

## Strange result when calculating Mean sym...

Maple
I am trying to use the Mean command of the Statistics package to calculate the arithmetic mean of a transformed random variable symbolically. I am using Maple 10. In my case the Mean command gives an incorrect answer. First a simple example, which gives me a correct result symbolically: restart;with(Statistics): X:=RandomVariable(Uniform(-Pi, Pi)); Mean(X+a);#it gives a, it is ok. #and here is my more complicated problem: restart;with(Statistics):X:=RandomVariable(Uniform(-Pi, Pi)); assume(Gt::RealRange(Open(0),Open(1)),Gr::RealRange(Open(0),Open(1))); Mean(abs(1-Gt*Gr*exp(-I*X)));

## Problem with calculating standard deviat...

Maple
I am calculating the standard deviation of an function with StandardDeviation command both symbolically and numerically and I get different result for the symbolic and numeric calculation. The result of the symbolic calculation is wrong. Here is my problem: restart;with(Statistics): X := RandomVariable(Uniform(-Pi, Pi)); f:=1/abs(1-0.5*exp(-I*X)); StandardDeviation(f); # It gives 0, which is wrong. StandardDeviation(f, numeric); Re(%); Any idea?
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