# Sample question: How do I compute symbolic integrals like $\int{sin(x) tan(x)} dx$

(Sample question) How do I compute the integral of $sin(x) tan(x)$ in Sage?

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First, make sure that you variable "x" is defined to be a symbolic variable:

sage: var('x')


then you can use the integrate command:

sage: integrate(sin(x)*tan(x), x)
-1/2*log(sin(x) - 1) + 1/2*log(sin(x) + 1) - sin(x)

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In addition, symbolic functions have an integrate method. For example, given the function $f(x) = \sin(x)\tan(x)$,

sage: var('x')
sage: f = sin(x)*tan(x)


its symbolic integral is calculated like so:

sage: f.integrate(x)
-1/2*log(sin(x) - 1) + 1/2*log(sin(x) + 1) - sin(x)


Be sure to provide the variable you wish to integrate with respect to as an argument to integrate.

more You can integrate sin(x)*tan(x) in Sage by using the integrate command:

sage: integrate(sin(x)*tan(x), x)
-1/2*log(sin(x) - 1) + 1/2*log(sin(x) + 1) - sin(x)


You can find some more examples in the tutorial.

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$\sum 2$ great

:-) like that !!

can you get (integrate) this (live-preview) functionality into the sage notebook text editor (tiny-mce) somehow ?

i'd like to see the formula there while typing

if i double-click directly on a formula tinymce opens plus a box with latex source code. but only the first time. how about the box popping up each time i place the cursor into a latex formula and then showing the typeset math. at the moment i don't see the use of the box ...

thanks for sage ... am loving it!!!

regards

Patrick

I guess, I am asking in the wrong place - (maybe "mis-")using this forum as a scratch pad - but the suggestion I'm making is somehow connected with this ... (I reached here from a blog bost).

So to be a bit more precise:

I am actually talking about the sage notebook. I am wondering what this light grey window is really good for and suggesting an way to make use of it.

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do you mean - how to access latex source for the equation here in this forum? Mouse over the formula and right-click. Then select "Show source".

Ehr - no - although that's also a real nice functionality i didn't know of (fancy menu shades! (but menu initially hidden under firefox default menu (ubuntu 10.04 - 64bit : http://oi56.tinypic.com/1hef4p.jpg)))

Sample answer: does TeX work, I wonder... $\int_0^{\infty} e^{-t^2} dt$

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well, if it is mathjax by default, formulas are inside  or . just a single $is a bad idea ^^ single$ is used for inline tex, double for block-style.