e) Multiple Choice: Over what interval does decrease?

To determine where the function decreases, you can analyze its first derivative . If over a specific interval, that means the function is decreasing within that range. Plotting the function or using a graphing tool can visually show you the intervals of decrease, making it easier to interpret.

Common mistakes include neglecting to consider points where the derivative is zero, which indicates possible local maxima or minima. Also, be cautious with endpoints; make sure you check the behavior as you approach infinity or negative infinity to fully capture the decreasing intervals.