I tried to use Mathematics symbols in web to search a formula directly,but I don't know how to insert mathematics symbols?
I can't find any Mathematics options in Ubuntu's Character Map application,
With Character Map, you can select a large range of non-standard and international characters (including math symbol which you need) to put in your documents.
No need to install it, because it was part of the default ubuntu installtion.
If you using gnome, go to Accessories --> Character Map
If you using unity, search "Character Map" in dash.
Or, run following command on terminal :
gucharmap
In Character Map menu, View > By Unicode Block. Then select "mathematical operators" on left sidebar.
Double click any symbol to copy.
