To add an Equation in a RichtextBox. Helpme Please!

Question

I'm Elitemod.
 I am a member of the forum www.c-sharpcorner.com
I have a problem thanks to help you:
I want to insert an Equation in a richtextbox is How?
If you can look forward attached example!
You can send mail directly to my: [email protected]
I look forward to receive a reply by you.
                               Sincere thanks!