# Mathematical expressions...

#### DesertFox

I hope it is not too absurd. I must ask for some help...
I have a very general question. What is the meaning of the following mathematical expressions?
1) q=1, M
2) i=1, N
3) m, M=0

About the first and the second expression, I have a guess... I think these expressions are just another notation for: q=1...M and i=q...N

But I am not sure at all, it's just my guess....

About the third expression... I think it notates that both m and M are equal to zero. But again, I am not sure whether this is the right meaning and expression.

I would highly appreciate every comment on the topic...
Have a nice day!:spin:

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#### skipjack

Forum Staff
(1) The notation q=1, M means that the variable q takes every integer value from 1 to M.

(2) The notation i=1, N means that the variable i takes every integer from 1 to N.

(3) The notation m, M=0 means that the variables (or constants) m and M are both zero, or, in certain contexts, zero initially.

The above notations do not need to be in bold. I wouldn't regard q=1...M as being a standard notation, though it would normally be taken to mean q=1, M (which is more compact).

1 person

#### DesertFox

I am very thankful for the explanation!!

I have one more question; it is about the notation of percent. Let's consider the following two expressions:

1) b = c + %c
2) b = c + <%>

Are they standard (conventional)? If the answer is YES, what exactly do they mean?

I am not sure whether I am right, but this is my suggestion:
1) b is the sum of c and per cent of c (it is not indicated how many percents of c, that's why i say some percents...)
2) b is the sum of c and some per cent (it is not indicated how many percent of what...that's why i say undefined per cent of something)

And what is the meaning of the special brackets <> in the second expression?

I will be glad for every reply!
Wish you all the best!!

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#### skipjack

Forum Staff
They both look strange to me, and I think they're not standard notation. Where did you find them? Was there any context that might indicate what they meant?

1 person

#### DesertFox

They both look strange to me, and I think they're not standard notation. Where did you find them? Was there any context that might indicate what they meant?
The source (the original text) is not reliable... it is not from a textbook.

help me, please, what does this mean:
(1;x)

According to me, it looks like notation of interval. But I don't understand the use of ";" instead of ","
In other word, according an interval must be written properly like this: (1,x)

So, what does the expression (1;x) mean?
Or again... this is not standard notation? it is confusing me

And one more question. What is the meaning of ordered pair written in square brackets. For example: [x,y]
Or maybe this is not a proper notation?
I know what is the meaning of the square brackets in intervals. But I don't know whether square brackets have any meaning when they notate ordered pairs....

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#### skipjack

Forum Staff
I haven't come across "(1;x)" before, so I don't know what it would be used for. Similarly, I haven't come across square brackets being used for writing an ordered pair.

Slightly off-beat notations may be used simply to refer to different parts of a textbook or article. They may also be features of a computer programming language. If most mathematics textbooks don't use a particular notation, it's reasonable to regard the notation as not being standard.

1 person