Re$-$derive an equation for ${}_{\text{m}\text{a}\text{x}},$ which will indicate whether or not your concrete section will be in the tension controlled region $($strain in the steel, ${}_s>0\mathrm{.}003+{}_y).$ We originally did this together during class. Why is ${}_{\text{m}\text{a}\text{x}}$ useful? Hint: What variable is dependent on ${}_s>0\mathrm{.}003+{}_y?$