<p>I have been doing practice tests and once came upon a symbol problem, where it gave me a symbol #, and asked me to solve something like this </p>
<h1>(#4)</h1>
<p>I have rifled through all my practice material, but have no idea where this problem went. I do not know how to solve it, but if anyone has done this one, it would be gladly appreciated if you could tell me where it is found. </p>
<p>This is what i remember from it.</p>
<h1>a= something..</h1>
<p>There is always a number attatched to the pound sign, but I had to distribute to get the answer for the one above.</p>
<p>SAT’s tend to put in a weird notation for a function. For example, if #a = a^2 + sqrt(a), then #4 = 4^2 + sqrt(4) = 18. Just substitute a with 4.</p>
<p>^ and continuing with that example, #(#4) means take the answer from #4 and use it as the input as you repeat the process. </p>
<p>So, in this case, #(#4) = #(18)=18^2 + sqrt(18)</p>
<p>It could be a binary function defined as #</p>
<p>These are called composite functions. See, in these kind of questions, what you do is calculate the result by substituting the given valve in ‘#’ function once. Then, enter the resultant value again as new input. These can very well be understood by ‘block diagrams’.
Consider this box:
input 1( given x value)—>[#]–input 2<a href=“AKA%20output%201”>i</a>*–>[#]____–> Final ANSWER.
Hope I make enough sense lol :D</p>