Skip to main content
lvl10720-Turquoise
20-Turquoise
Nov 3, 2014 12:39 PM UTC
Solved

A Function and Three Output

Hello Everyone,

A+Function+and+Three+Output.PNG

I need help with explanation of each output.

Thanks in advance for your time and help.

Regards.

StuartBruffAnswer
23-Emerald V
Nov 3, 2014 4:50 PM UTC

Loi Le wrote:

Hello Everyone,

A+Function+and+Three+Output.PNG

I need help with explanation of each output.

Thanks in advance for your time and help.

Regards.

I'm guessing that you are querying why you have 3 different results?

As Werner says, the first result is correct ... as is the last result (it's just a substitution of x by e!) ... but I am intrigued by why the second result has been calculated in floating point.

You could look at the limits to see what the problem is at e ..

Stuart

collab+-+14+11+03+function+and+five+outputs.JPG

View in thread

4 replies

Werner_E
Werner_E25-Diamond I
25-Diamond I
Nov 3, 2014 1:24 PM UTC

You should know that only the first result is correct and the other two are kind of "random numbers" due to bad round off errors. After all you try to divide by zero in a rather bizarre way.

Whats the point of this question? What are you trying to achieve?

Translate
StuartBruff23-Emerald VAnswer
23-Emerald V
Nov 3, 2014 4:50 PM UTC

Loi Le wrote:

Hello Everyone,

A+Function+and+Three+Output.PNG

I need help with explanation of each output.

Thanks in advance for your time and help.

Regards.

I'm guessing that you are querying why you have 3 different results?

As Werner says, the first result is correct ... as is the last result (it's just a substitution of x by e!) ... but I am intrigued by why the second result has been calculated in floating point.

You could look at the limits to see what the problem is at e ..

Stuart

collab+-+14+11+03+function+and+five+outputs.JPG

Translate
Werner_E
Werner_E25-Diamond I
25-Diamond I
Nov 3, 2014 6:13 PM UTC

StuartBruff wrote:

As Werner says, the first result is correct ... as is the last result (it's just a substitution of x by e!) ... but I am intrigued by why the second result has been calculated in floating point.

Yes, thats surprising. Guess it has something to do with the in(element of) operator/iterator.

1.png

Here are some more surprising results:

2.png

The 23.14... are e^pi instead of e^(-pi).

Translate
zhulaojianke1-Visitor
1-Visitor
Jan 18, 2015 11:56 AM UTC

When I use "simplify", the problem seems be solved.

The "For" loop, I think the MuPad has looked it as a numerical calculation, and use a 10^-15 error on it; and the Maple has calculated it in symbolic totally.

Here is the Mathcad 15 result. I use e-10^-15 to correct the numerical error, and I get a good result.

2015-01-18_181910.jpg

The plot of the last function:

2015-01-18_194904.jpg

When the variable of the "For" loop output is a little large than e, even 10^-15, the function result is e^(pi).

And I have used the Mathcad 2001i to calculate the worksheet above without use the 10^-15 error correction, and have got a good result.

2015-01-18_192725.jpg

Translate
Terms & ConditionsAccessibility statement