Finding the stationary point is about setting the first derivative to zero and solving. To prove it's a maximum, your second derivative at that point must be negative. This is the rule they taught me in my online course.
But, ah, the real proof? It’s in the doing. Last week I spent an hour trying to find the 'stationary point' of my phone's brightness—only to realize I was adjusting the volume instead! So check your work slowly, or you’ll prove a maximum when you have a minimum, just like I did.
#exams#study
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