Alevel H2 Maths 2015 Paper 1, Question 11
2015 examiner’s report on ii: The explanations given of the maximum point were generally poor. A majority of candidates attempted to differentiate dy/dx = 2cotθ – tanθ with the left-hand side differentiated with respect to x and the right-hand side with respect to θ. Other candidates produced a table of non-specific points claiming to be close to the turning point and to be sufficient for the first differential test.
Solution for Part ii, explanation of why it is a maximum