Hi ^^^11^^^,
I agree with you. There are various topics involving differentiation (chain rule, differentiation of products of functions, or their quotients etc), but more than 50 % of students solved the problems involving these topics. The only exception is a group of tough differentiation problems (I classify them as Miscellaneous) that involve absolute values of functions, or discontinuous functions, or finding the maximum of a gradient etc. Those problems do not pop up often of late for some reason, and the examples of them are:
* 2007, Q 3a in Test 1 and Q 3c in Test 2B
* 2009, Q 10a in Test 1, Q 5 in multiple-choices test and Q 1e ii in Test 2B
* 2011, Q 7 and 9 in multiple-choices test
* 2015, Q 2b in Test 2B
As for integration, it also covers quite a few topics. Students generally do well with the approximation of area under curve, or identifying a function if its derivative and a point are given. What seems to cause a lot of grief are topics like:
* If x*f'(x) is given, calculate the integral of x*f(x)
* Calculation of area under a curve, or between two curves
* If function contains a coefficient of unknown value, and and the area under the function is given, calculate the value of the coefficient
* Some really quirky problems like
- 2008: Q 19 in multiple choices test, Q 2d in Test 2B
- 2010: Q 22 in multiple choices test
- 2013: Q14 in in multiple choices test
Cheers