Question

how to subtract radians?

Answer 1

You first need to make sure the denominators are equal, then when they are, you can add/subtract the numerators. Then you can place the result over the common denominator.

I hope this helps! :) 

Answer 2

Usually radians are represented by a number of π.

Example: 2π or (3π/2) or -π/5, etc.

If I have to add 2π+3π = 5π

if I have to add (3π/2  +  π), I reduce to the same denominator:

3π/2  +  π ==> 3π/2  +  2/2π ===> 5π/2