mjhjmtu

I would like to create variables to hold strings like f(x)=3x+1 to be inputted into an exam questions.

I can create variables like funA, funB, … et cetera. The problem is how do I reference them using A, B, … et cetera.

documentclass[12pt]exam

% conditional statements
usepackagexifthen

newcommandexamA

newcommandfunA$s(t) = 12t^2 -7t + 16$
newcommandfunB$s(t) = 16t^2 +3t + 10$
newcommandfunC$s(t) = 12t^2 + t + 10.$

begindocument

beginquestions

question % I would like funexam to return funA when exam = a. Sadly it doesn't 

The position of an object moving along a straight line is given by funexam. Find the average velocity of the object over the interval $[1,1+h]$ where $h>0$ is a real number.

question % this works but is a lot to write when accommodating 10 stored functions

ifthenelseequalexamA
 
 newcommandfunction$s(t) = 12t^2 -7t + 16.$
 
 
 ifthenelseequalexamB
 
 newcommandfunction$s(t) = 16t^2 +3t + 10.$
 
 
 newcommandfunction$s(t) = 12t^2 + t + 10.$
 
 

The position of an object moving along a straight line is given by function Find the average velocity of the object over the interval $[1,1+h]$ where $h>0$ is a real number.

endquestions
enddocument

TeX allows you to reference control sequence names using a csname...endcsname pair. Any command inside this csname...endcsname pair will be expanded (i.e.: replaced by its meaning) until only unexpandable tokens are left, then TeX creates a control sequence out of the contents passed to csname...endcsname.

For instance, if you have newcommandexamA, then csname funAendcsname and csname funexamendcsname will both expand to funA. You can create a wrapper command to avoid writing csname...endcsname every single time:

documentclass[12pt]exam

newcommandexamA

newcommandfun[1]csname fun#1endcsname
% or:
% newcommandfuncsname funexamendcsname, then use just fun instead of funexam
newcommandfunA$s(t) = 12t^2 -7t + 16$
newcommandfunB$s(t) = 16t^2 +3t + 10$
newcommandfunC$s(t) = 12t^2 + t + 10$

begindocument

beginquestions

question

The position of an object moving along a straight line is given by funexam. Find the average velocity of the object over the interval $[1,1+h]$ where $h>0$ is a real number.

endquestions
enddocument