Finally – stuck
And it feels, er, kind of good. I’ve been battering my head against a torus-integral problem for hours.
Pretty sure I won’t solve it but not for lack of trying.
On the plus side, it has consolidated everything in unit 25 – multiple integrals – but not sufficiently so to actually get the answer.
In a weird way, it’s nice when that happens. I look forward to my tutor’s model answer.
Edit: slept on it and it seemed all too obvious this morning. Sneaky enough question, though.