There are a couple of ways to add mathematical graphics to your post.
- Via the upload button or
- Via a desmos link
Note that this question only concerns how to add these things once they’ve been created. The actual creation of images in the first place is outside the scope of this question but you can ask about that kind of thing in the code category.
Image upload
When you’re in the editor, you should notice a toolbar at the top:
Just click on the Upload button as shown. The process should be self-explanatory. You can upload an image from your computer or link to an image on the web.
Desmos link
Desmos is wonderful site that allows you to create interactive graphics online. After you create such a graphic, simply click on the Share Graph button near the upper right. A link will popup that you can paste into your editor here. That’s all there is to it!
If you want, you can choose the embed option and copy the slightly more complicated iframe code to paste here. That allows you to specify some iframe attributes, like size and border style. That’s how the graph below was included:
The image shows the graph of y=sin(ax) and is interactive. You can move the slider to change the value of a and see the effect. If you click on the “edit graph on desmos” link in the lower right, you can see how the graph was created in the first place and edit your own copy, if you like.