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#1 Help Me ! » Show that the equality stands » 2014-10-16 07:24:29

evinda
Replies: 0

Hey!!!

I want to show that: 


That's what I have tried:

When

, it means that:

So that

So,

.

Is it right so far? Also, how can I show that

?

#2 Help Me ! » married couples-how many ways » 2014-04-24 09:34:49

evinda
Replies: 33

Hello!!!:)
Could you help me at the following exercise?
With how many ways can we choose a man and a woman that are not married to each other from n married couples?

#3 Re: Help Me ! » find rounding of a number!! » 2014-02-14 06:09:58

evinda
bobbym wrote:

Hi evinda;

It is a handy little calculator is it not?

Yes,it is! smile

#4 Re: Help Me ! » which is the right result? » 2014-02-06 02:40:01

evinda
bobbym wrote:

The exact value is 3 / 10, now what did you get for your floating point value?

I got

..Is this right?

#5 Re: Help Me ! » which is the right result? » 2014-02-06 02:33:15

evinda
bobbym wrote:

Is this what you are calculating?

Yes, I calculate the real value of this

and its value as a floating-point number.
So,the result I am looking for should have the form

#6 Re: Help Me ! » which is the right result? » 2014-02-06 02:07:46

evinda
bobbym wrote:

What is your result?

I found

.

#7 Re: Help Me ! » which is the right result? » 2014-02-06 01:54:40

evinda
bobbym wrote:

Hi evinda;

I am afraid I do not understand what you want. What do you want to check the relative error for?

I found the relative error

but I don't know if the result that I found is right.

#8 Help Me ! » which is the right result? » 2014-02-05 22:50:49

evinda
Replies: 9

Hey!!I have a question..
Suppose  base=10 , precision t=3, -L=U=10 and


I want to calculate the relative error for B.
We don't make rounding.For example,if we have the value 345.924 it is equal to
and the corresponding floating number is
.

Could you tell me which is the result,so I can check mine?

#9 Re: Help Me ! » How can I know the number of all the possible parse trees? » 2014-01-26 10:58:38

evinda
anonimnystefy wrote:

I think there are 6 of them here, since the difference between the trees will be in which order do you go through the operations (that is, those elements that correspond to P). You can go -+*,-*+,+-*,+*-,*-+ or *+-.

Ok..thank you very much!!! smile

#10 Help Me ! » How can I know the number of all the possible parse trees? » 2014-01-26 05:54:34

evinda
Replies: 3

Hello!!! smile
Let

the following grammar with
and with start symbol
:



I have to make all the possible parse trees for the word

But how can I know how many possible parse trees there are?Is there a formula with which I can find the number of all the possible parse trees?

#11 Re: Help Me ! » find rounding of a number!! » 2014-01-06 13:32:32

evinda
bobbym wrote:

Normalizing the number means to get the mantissa to be a single digit (not zero ) and can be positive or negative.

That is normalized and has 5 significant digits.

But did they want you to nomalize?

Try this handy dandy little calculator:

http://www.mathsisfun.com/rounding-numbers.html

Great!!!!Thank you so much for your help!!!!! smile

#12 Re: Help Me ! » find rounding of a number!! » 2014-01-06 12:42:15

evinda
bobbym wrote:

Hi evinda;

What does t = 5 mean?  5 places? 5 significant digits? An error of .5?

5 significant digits!!!

#13 Help Me ! » find rounding of a number!! » 2014-01-06 09:13:48

evinda
Replies: 8

Hello!!
How can I find the rounding of the number 0.0238095238095,with precision t=5 ?
First I have to find the float number,that is 

,right?
Is then the rounding :
or am I wrong??

#14 Re: Help Me ! » how can I analyze expression,based on Chomsky form? » 2014-01-04 09:03:18

evinda

Since the expression starts with

  the first rule for S that we take is
,then from the first rule,we have
and then the next rule for S is  r  ,so we have S -> t+r+S and at the last step we replace S with its rule
. Is this the analysis?Or do I have to do something else??

#15 Help Me ! » how can I analyze expression,based on Chomsky form? » 2014-01-02 12:35:58

evinda
Replies: 1

Hello!! big_smile
Given the following grammar in Chomsky form:

   ,

how can I analyze the expression

,based on this Chomsky form?

#16 Re: Help Me ! » perfect square-proof » 2014-01-02 12:31:13

evinda
anonimnystefy wrote:

I am not doing that, because that statement is true.

In case you have not read the first post, which seems to be the case, it asks us to prove that, if j is a square number and r an integer, j+i*r is not always a square number.

Ok,I will read it..thank you very much!!!! smile

#17 Re: Help Me ! » perfect square-proof » 2013-12-27 11:30:22

evinda
bobbym wrote:

You did that with a counterexample. I am not seeing how to do it by contradiction yet.

Ok...Thank you very much for your help!!! smile

#18 Re: Help Me ! » perfect square-proof » 2013-12-27 10:19:19

evinda
bobbym wrote:

Remember, it sometimes works! Trying to prove that it never does work is bound to fail.

And can't I show that it is not always true?

#19 Re: Help Me ! » perfect square-proof » 2013-12-27 09:54:22

evinda
bobbym wrote:

The great thing about doing numerical mathematics is you do not ever have ask the question, is it right. You did the calculation, you know it is right.

Yes, there are many counterexamples. The assertion is clearly false unless there are more conditions that you have omitted.

Why do you need anymore than that to convince anyone?

I wanted to prove it by contradiction and tried this:
for

: Since j is a perfect square,
. If
is also a perfect square, then
.
But I didn't know how to continue..

#20 Re: Help Me ! » perfect square-proof » 2013-12-27 09:30:33

evinda
bobbym wrote:

Did you find a counterexample?

For



for
,so it is a perfect square
for
,that is not a perfect square
for
,that is not a perfect square.
Right?

#21 Re: Help Me ! » perfect square-proof » 2013-12-27 09:17:35

evinda
bobbym wrote:

That would do it.

Nice,thank you smile and,is there also an other way,or is it the only one?

#22 Re: Help Me ! » perfect square-proof » 2013-12-27 09:01:05

evinda
bobbym wrote:

I think you can easily disprove it by a counterexample.

Do you mean that I have to take specific values for j and r?

#23 Re: Help Me ! » perfect square-proof » 2013-12-27 07:27:14

evinda
evinda wrote:

Hello!! smile
I have a question.
If we know that j is a perfect square,how can we show that j+i*r is not always a perfect square for each i

,where r is>0?

Can I prove it by contradiction? hmm

#24 Help Me ! » perfect square-proof » 2013-12-26 08:14:45

evinda
Replies: 30

Hello!! smile
I have a question.
If we know that j is a perfect square,how can we show that j+i*r is not always a perfect square for each i

,where r is>0?

#25 Re: Help Me ! » Regular expression » 2013-12-16 10:45:24

evinda
anonimnystefy wrote:

Below is what I am getting.

I got a similar!!! smile Thank you very much!!!! wink

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