middle dot meaning?

[cruz33]

What does this mathematical expression mean?

7 . 3

But, with the dot in the middle, not at the bottom. I can’tfind a way to type a dot in the middle.

Thanks!

 

[DrPhil]

What does this mathematical expression mean?

7 · 3

But, with the dot in the middle, not at the bottom. I can’tfind a way to type a dot in the middle.
Alt-0183 --> ·

Thanks!

-In some countries the center dot is the normal position for the decimal point 7·3 = 7.3

In the US, the center dot is multiplication: 7 · 3 = 21

 

[lookagain]

What does this mathematical expression mean?

7 . 3

But, with the dot in the middle, not at the bottom. I can’t find a way to type a dot in the middle.

Thanks!

cruz33, try typing thie following in Latex: $\displaystyle \ \$ [ tex]7 \cdot 3[ /tex] $\displaystyle \ \$ But don't have any spaces between the open bracket and the "t" of "tex]." Also, don't have any spaces between the open bracket and the "/" of "/tex]."

 

[cruz33]

that's what I thouht...

-In some countries the center dot is the normal position for the decimal point 7·3 = 7.3

In the US, the center dot is multiplication: 7 · 3 = 21

That's what I thought it meant, but WHY a dot is used instead of an x, like 7x3, like I have always seen it, why use a dot instead? Sorry, I am a very inquisitive person. Is there a reason why a dot is used instead of the "normal" way of writing a multiplication problem?

 

[JeffM]

That's what I thought it meant, but WHY a dot is used instead of an x, like 7x3, like I have always seen it, why use a dot instead? Sorry, I am a very inquisitive person. Is there a reason why a dot is used instead of the "normal" way of writing a multiplication problem?

Nothing wrong with being inquisitive.

In algebra and higher mathematics, letters are used to stand for a number that is not yet known or specified. So x might be a number instead of an operator. So, to avoid confusion, a new symbol was needed for multiplication. Some people use the dot to mean multiplication; more nowadays use the asterisk.

 

[cruz33]

got it!

Nothing wrong with being inquisitive.

In algebra and higher mathematics, letters are used to stand for a number that is not yet known or specified. So x might be a number instead of an operator. So, to avoid confusion, a new symbol was needed for multiplication. Some people use the dot to mean multiplication; more nowadays use the asterisk.

Interesting! Thanks for the explanation!

 

[Deleted member 4993]

The middle dot - or · - is still used in vector multiplication as a sign for scalar product.

 

[cruz33]

thank you!

The middle dot - or · - is still used in vector multiplication as a sign for scalar product.

Thanks for the additional info! I had to goggle "vector multiplication" though, so I learned another mathematical concept!

 

[Deleted member 4993]

Thanks for the additional info! I had to goggle "vector multiplication" though, so I learned another mathematical concept!

Remember however that you just learned about the "word" vector multiplication.

Vector multiplication is pretty complicated and deep stuff - the concept is pretty difficult.

Just food for thought - although we have vector multiplication, we do not have vector division defined.

 

[cruz33]

got it!

Remember however that you just learned about the "word" vector multiplication.

Vector multiplication is pretty complicated and deep stuff - the concept is pretty difficult.

Just food for thought - although we have vector multiplication, we do not have vector division defined.

Just learning the meaning of the word is enough for me, don't want to go deep, I'm already overwhelmed with what I'm learning now in my current math class!

 

[mmm4444bot]

more [people] nowadays use the asterisk.

You're speaking about texting, yes? :cool:

I never write an asterisk, when using paper and pencil. I also use centered dots when formatting math (eg: equation editors, diagrams, LaTex, et cetera).

 

[JeffM]

You're speaking about texting, yes? :cool:

I never write an asterisk, when using paper and pencil. I also use centered dots when formatting math (eg: equation editors, diagrams, LaTex, et cetera).

Well actually I was thinking of calculators, spreadsheets, etc. I tend to use a dot myself when using paper and pencil, but that is because (a) I am old enough that dots were what I was taught in algebra as a child, (b) dots are quicker to write than asterisks, and (c) it is useful to have a symbol for an unspecified operation, and the asterisk was used for that purpose back when I studied abstract algebra.

 

[mmm4444bot]

actually I was thinking of calculators, spreadsheets, etc.

Okay -- agreed -- more people type asterisks for that purpose than do centered dots!