Use the symbols provided below to sketch the phase line for the differential equation
$$x^{\prime} = -2x\!\left(1-x\right)\!\left(4-x\right) .$$ This differential equation could model a population that will become extinct if it drops below a particular critical value.

To place a symbol on the line click a symbol button then click a point on the line.
To remove a symbol from the line click the "delete" button then click the symbol on the line.