Thanks Genghis
Yes it is an exam question.
Ive learnt these graphs from a book that show the 4 main speeds in the order of E R T M, where E= EAS, R= RAS etc.
For instance the graph that shows constant TAS (by having the TAS line on the graph as a vertical line) show that the Mach speed increases and RAS to decrease.
Hence this is what I put for my answer to the first question which I now know is wrong.
Its quite hard to describe these graphs without producing the actual graph, although they are very simple. Are these not valid then for entering an isotherm or inversion?
Many thanks again,
ST