What's the correct syntax for inspecting a BOOLEAN in a formula?

#1

I’ve tried…

if this == True then...
if this == 'True' then...
if this is True then...

??

#2 
if this then ... elsif ... else ... end
#3

I hope it’s alright to respond to a post with an accepted solution.

I found this post in searching for a specific topic, and combined with efforts from this post, and this post to get what I was seeking.

I have two booleans and need them to be inverses of one another.
So when boolean_1 is true, I need boolean_2 to be false, and vice versa.

The formula I wrote for boolean_2 that I found to work is:
if boolean_1 then false else true end