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Graph.tk

graph.tk

147 pointsbreck38 comments

For those who don't know, all Macs come with "Grapher"; it's really good. Here's a Grapher screenshot of the equation used in Graph.tk:

http://i.imgur.com/ql0Y23a.png

Having shared that, this is a really cool thing for the web.

Grapher is such a handy tool. Unfortunately, it hasn't received any updates since its introduction. There are a couple bugs, e.g. when right clicking on an equation in the sidebar, the context menu does not appear properly.

I can't believe that Apple doesn't advertise this more. It is rather powerful http://i.imgur.com/3LN7o.png and extremely easy to use. It is especially useful for introductory college-level Math given its 3d graphing capabilities (calc 3) and ability to plot slope fields (diff-eq).

Tip: Round the x and y values of grid lines to the nearest pixel so that you don't have the effect where most of them are drawn over two rows/columns of pixels. It makes it look much sharper.

Interestingly, the expressions are the same, but the graphs are not, which means one of the two is wrong.

I haven't seen a .tk domain in years... You used to be able to get a free domain (with ads overlayed) on it.

They're still available for free, no ads on it, but if you get too much traffic or something they yank the DNS and point it at an ad server

With the reason "Abuse and Copyright Infringement" no less. If you attempt to re-register the domain, it will either be unavailable or become a premium domain for which you need to pay.

Comments from two years ago, when this first came out: https://news.ycombinator.com/item?id=2120610

Also: https://news.ycombinator.com/item?id=2110106

The interactive formula rendering is done using MathQill by the way.

[1] http://mathquill.com/

It looks like the last commit was a couple of years back so this isn't very new, though I hadn't seen it before and it's very impressive.

https://github.com/aantthony/graph.tk

First .tk not to be used for spam or malware in years!

Great web app, though.

No. Tcl uses this domain. www.tcl.tk

dot tk... as a kid, did anyone else enjoy getting their first (free) domain from that register?

Yep. I even have a few free 4-letter domains from it, which is rather rare nowadays for any TLD (though probably not too valuable here, especially since you can't really do "-tk" domain hacks).

What do you mean by "-tk" domain hacks?

del.icio.us was a "domain hack". He's talking about the fact it is hard to construct one with a .tk domain as there are so few English words that end with tk (if any?).

tcl.tk?

That's one of the very few exceptions. I don't think any words in English end in -tk, and few end in -t[vowel][k-sound].

Yes! First thing I thought of when I saw this submission.

Ahh, nostalgia! Remember also signing up for all those horrible free web hosting services and combining them?

This reminds me of another website (which I use frequently)

https://www.desmos.com/

Everyone should check it out.

See Desmos https://www.desmos.com/calculator if you need to store and share graphs.

Nice one. Wish I can easily grab a certain generated graph and use it as a waveform in a synth. Just for... science.

Pretty cool. Posted by the author? Do you cut off rendering purposefully when axis gets around 1x10^153 or is that an artifact of the program?

Consider changing the TLD, as sites such as Facebook block sharing free domains for spam reasons. Tried to share this with some friends, no dice.

Yep, I'm changing it to equation.io as soon as I get the new one working.

The sample plot is wrong. Domain of sin x + log(x+1) derivative is R - {-1}, so there must not be any vertical line at x = -1.

Most graphers have that problem - detecting a discontinuity numerically isn't trivial.

Any references on who had used this? The web page totally phugges my browser (Chrome).

Fun fact: Facebook won't let you post this domain. Maybe the .tk ?

How can I draw a circle using this app?

r=1, check the ? (help)!

The quality of graphs is pretty bad.

http://i.imgur.com/sRyxzN5.png

Compare it to WolframAlpha

http://www.wolframalpha.com/input/?i=d%2Fdx%28sin%28x*x%29+%...

That's probably because the author is able to devote less resources per client than Wolfram?

The graph.tk graph is displaying from ~-300 to ~300 while the WolframAlpha graph is only displaying from -10 to 10. That is hardly a fair comparison.

If you change the x-axis to be roughly the same range as on graph.tk, it turns out like this:

http://www.wolframalpha.com/input/?i=d%2Fdx%28sin%28x*x%29+%...

This is actually a browser issue. AFAIK, Chrome and Firefox both round subpixels (e.g. 1.6px -> 2px). If you try doing the same thing in Safari you will notice that the graph looks as smooth as butter.

http://i.imgur.com/XzDgKtP.png

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