# definite integral typing help

• April 6th 2009, 06:38 PM
Jim Marnell
definite integral typing help
how would i type $\int$ and include the "from x=1 to x=3" in a definite integral problem
• April 6th 2009, 06:41 PM
Mush
Quote:

Originally Posted by Jim Marnell
how would i type $\int$ and include the "from x=1 to x=3" in a definite integral problem

$\int_{x=1}^{x=3}$

Click on the image to see the code.
• April 6th 2009, 06:53 PM
Reckoner
Quote:

Originally Posted by Jim Marnell
how would i type $\int$ and include the "from x=1 to x=3" in a definite integral problem

I know you have your answer, but as I like proper spacing and you are asking about the code for integrals, I feel like noting:

In between the integrand and the $dx,$ you should add a \, to get the appropriate spacing.

Code:

\int_a^bf(x)\,dx
gives

$\int_a^bf(x)\,dx$

which looks nicer than

$\int_a^bf(x)dx$

(especially for iterated integrals).
• April 6th 2009, 07:25 PM
Jhevon
i like to use "~" instead of "\," or "\;" ...but i think this has all been discussed before...
• April 8th 2009, 10:47 PM
da kid
Quote:

Originally Posted by Reckoner
I know you have your answer, but as I like proper spacing and you are asking about the code for integrals, I feel like noting:

In between the integrand and the $dx,$ you should add a \, to get the appropriate spacing.

Code:

\int_a^bf(x)\,dx
gives

$\int_a^bf(x)\,dx$

which looks nicer than

$\int_a^bf(x)dx$

(especially for iterated integrals).

does adding a \, always produce a little extra white space? are there common instances where doing this creates a problem or error message? i am just learning latex but i notice that a lot of times things get squished together. i like a cleaner look too.
• April 9th 2009, 12:06 AM
Opalg
Quote:

Originally Posted by da kid
does adding a \, always produce a little extra white space? are there common instances where doing this creates a problem or error message? i am just learning latex but i notice that a lot of times things get squished together. i like a cleaner look too.

TeX provides four spacing commands for use in math mode. they are \, (thin space), \: (medium space), \; (thick space) and \! (negative thin space). On the whole, TeX and LaTeX are pretty good at getting the spacing correct, but there are some occasions where you need to use the spacing commands to improve the appearance of a formula. One of these is the thin space before dx in an integral. Another one that I often use is a negative space (or two) after the integral sign. I think that $\int\!\!f(x)\,dx$ looks better than $\int f(x)\,dx$.