as i said, to me your reasoning was sound, but it seemed strange that they were giving you all these limits that don't exist, so i decided to double check with a CAS. both matlab and maple gave answers for the limits, so i assumed it was convention. similar to how you can say

, even though the function is not defined to the left of zero. it seems that if the function is continuous at the point in question, the limit is taken to be that value. i suppose you were expected to be more strict and use the

definition of the limit. sorry you lost the marks.