I am so sorry, but I don't know what any of that is. I've spent hours trying to understand. I've done tons of questions (correctly) but I just don't know what to write as the answer to this question. I was seriously hoping someone could tell me what equation or statement actually answers the question that was asked. But so far on three different forums the only replies I get are people asking me questions, giving vague hints I don't understand or telling me to research functions. I'm fairly close to tears now... so tired of trying and only failing to understand.