Barclays Intern interview questions

Graph y= 3X^3 - 3. On said graph, find the point where the tangent line makes a 45 degree angle with the horizontal. Create a class to sort a list of integers of unspecified length. Also had the typical HR questions, i.e. "Why are you interested in the position?", "What makes you qualified for the position", etc.

The interviewer asked me a few questions which I felt were just for the sake of asking.