Version : √ OneNote for Windows 10
√ OneNote Online
The “Graph in 2D” feature introduced in May 2017 is being improved gradually, and is now able to do much more than its simple name implies : let’s have a look at this amazing feature for student !
[instead of illustrating this blog post with usual linear curves, parabolas or hyperbolas… I choose emblematic curves instead, and mentioned the name of the mathematicians having discovered or studied them : enjoy this journey into the world of Mathematics !]
Simple curves
Obviously, you can plot the curve of an equation with unknowns x and y, in a Cartesian coordinate system.

Note in the above example that the equation doesn’t need to be written such as y = f ( x ).
You may even insert the graph on your note after resizing the plot area if necessary. The pasted graph is not interactive though, so you’d better ajust the zoom first.
Curve with parameters
More useful, you can add parameters to your equation, in order to change the proportions of the curve :

Multiples curves
You may also plot several curves on the same graph, providing you group them with a brace.
See the illustration below, in a tweet I wrote when I discovered this feature :
I just noticed that #OneNote for #Windows10 can plot multiple equations. I tried up to 10, and it worked flawlessly ! cc/ @OneNoteC @kurtsoeser @sig225 pic.twitter.com/fH6fIEr9Fx
— Albin LABELLE (@Noteadviser) July 21, 2018
Please note that :
– the legend may be exhibited moving the cursor over the ⓘ symbol at the bottom left,
– the legend are not carried forward when you drag the graph in your note,
– the color of the curves in the graph do not match those of the inked equation.
Also, I tried to plot both equations above in the same graph (clover and lemniscate) but it didn’t worked : OneNote offered no option in this instance, except ink to math…
Inequalities

Nevertheless, you can’t combine both features above (multiple curves and inequalities), as illustrated in this tweet :
Unfortunately not, although it can plot inequalities nicely if written in a single line. pic.twitter.com/jmRif6yvFL
— Albin LABELLE (@Noteadviser) July 24, 2018
Fonctions
Microsoft’ announcement stating that OneNote may support functions puzzled me for a while…

In fact, it seems that Microsoft was simply announcing support for multiple equations plotted in the same graph, as illustrated in the previous section.
And I am not merely quibbling about wording (function or equation ?) : as a matter of fact, experimenting with the same equation written in similar ways (equation & function), I noticed that OneNote makes a confusion with the f in f ( x ) , believing it’s a parameter…
Furthermore, writing fx instead of f ( x ), you’ll get the same result.
So, what’s the purpose of the new command “Graph both sides in 2D” ?
Intercepts
The only usage I can think of, is to show the intercept of two equations (one on each side of the equal sign) :

Key features
Finally, OneNote may sometimes mention the key features of your equation such as minima, maxima, intercepts, asymptotes, inflexion points, range, domain… and show them on the graph.
Shortcomings
Sometimes though, OneNote is not able to plot an equation :

Now it’s your turn to share your nicest curves !
Reference : All curves illustrating my blog post were found on Mathcurve.
Updated 21/08/2018 : now available in OneNote Online as well :
#Office365 subscribers can now enjoy ink math assistant in #OneNote Online! Get to know this awesome #edtech here: https://t.co/0s5TlnshGD #STEM #MathChat pic.twitter.com/Z5T5RQ2vgP
— OneNote Education (@OneNoteEDU) July 31, 2018
Nota 22/09/2018 : Graph Inequality seems to be broken :
Nota 14/02/2019 : Valentine day ! Can’t resist to share this amazing curve !
❤ #Mathematics
❤ #OneNote
Happy #ValentinesDay pic.twitter.com/nwD2VxciLL— Steven Payne (@standouted) 14 février 2019