Usually WolframAlpha understands what logical expression I have entered but sometimes I can't find a way to do it especially when you are using equivalent sign.
For example if I have $$ p \land q \Leftrightarrow \lnot q$$ I type (p AND q) equivalent (NOT q) and it doesn't work, I have tried other various methods it didn't work either.
Use
XNORinstead ofequivalent.