+Rb1IsH1 You can, I believe he's teaching for a specific syllabus which wants you to do it using gradients either side, but second order derivative is quicker, so unless they specifically say "by considering points either side of the turning point" it will be alright to use the second order derivative, I think anyway...
Thank you sir your videos are much more concise and clearer than Mr Arnold's - u legend!
What about when they say the range??? Example 5 in the book.. Sir..?
Can't you just do second order differentiation to find if a curve is a maximum or minimum?
+Rb1IsH1 You can, I believe he's teaching for a specific syllabus which wants you to do it using gradients either side, but second order derivative is quicker, so unless they specifically say "by considering points either side of the turning point" it will be alright to use the second order derivative, I think anyway...