Minima and Maxima questions are often difficult, but there are super easy ones too (the classic cylinder one). Does anyone have a general method which helps in solving these?
Hey Oliver! The method can be generalised into 3 steps:
1 - Form Two Equations with Three Variables
2 - Use Elimination to Remove One of These Variables
3 - Differentiate to Find the Maxima/Minima
Most maxima/minima questions follow this broad process. Sometimes they will lead you through Steps 1-2, or even give you the result you need to prove in the question, but the third step is always the same.
Getting good at these is all about practice!
PS: Common mistake, don't forget to actually prove that what you've found is the maxima/minima you are after using the second derivative test (or equivalent)!