Is there a way to check if a value is inside a table?

In a simpler form: I am creating a script that contains true/false questions I have a table that contains questions, and two other tables. Those two other tables are named trueq1 and falseq1; and they contain values of questions that correspond to the table name. I need someone that can either link me to a wiki page or explain to me if there is a function that can check for values inside of tables. (i.e check if this value is under the trueq1 table or the falseq1 table)

In script form:

rqs1 = {"q1","q2","q3"}

trueq1 = {rqs1[1], rqs1[3]}
falseq1 = {rqs1[2]}

function isThisInTrue()
--check if this value is listed in the trueq1 table
end