Typo in set 6 solutions

Hi everyone 

A couple of you have pointed that in P21, part (b) the answer for the first component of the Riemann tensor is zero - that is true, but there is a typo on my part! It should read R^1_{212}, not R^1_{211}. Sorry about that. 

I have updated the solutions to reflect that change. Hopefully I have also written up the other nonzero components correctly :) 

In general, please do let me know if answers in the solutions don't agree with what you've done. The feedback is appreciated and useful. It's always possible (probable, even) that I've made an error somewhere. 

Have a good weekend. 

Jake