Suppose you want to solve the problem $P(x)=0.25$ for $x$. You may be tempted to use the SOLVE command on your calculator. Let us assume you have $n(x)$ stored as $\mathrm{y} 1(\mathrm{x})$ then you would enter

$$\text { Solve }\left(\int(\mathrm{y} 1(\mathrm{t}), \mathrm{t}, 0, \mathrm{x})=0.25, \mathrm{x}\right)$$

While this will yield an approximate solution for $x,$ it may take some time for the calculator to solve the problem (in a few minutes the calculator does gives as its solution 0.67449 ). As an alternative, use the approximation for $P(x)$ given in the previous exercise and solve it for $x$. That is, enter this approximation as $y 2(x)$ and then enter

$$\text { Solve }(\mathrm{y} 2(\mathrm{x})=0.25, \mathrm{x})$$