To have demonstrated the method in different ways (5)
I believe the answer is:
shown
'to have demonstrated' is the definition.
I can't tell whether this defines the answer.
'method in different ways' is the wordplay.
'method' becomes 'how' (I've seen this in another clue).
'in' means one lot of letters goes inside another.
'different ways' becomes 'sn' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'how' going into 'sn' is 'SHOWN'.
'the' is the link.
Can you help me to learn more?
(Other definitions for shown that I've seen before include "Demonstrated" , "Displayed" , "Exhibited" , "Explained" .)