Cambridge mathematician with right approach to resistance (8)
I believe the answer is:
wrangler
'cambridge mathematician' is the definition.
(term for a mathematician at Cambridge University)
'with right approach to resistance' is the wordplay.
'with' becomes 'w' (abbreviation).
'right' becomes 'r' (common abbreviation).
'approach' becomes 'angle' (as in a journalist's approach to a story).
'to resistance' becomes 'r' (electronics abbreviation).
'w'+'r'+'angle'+'r'='WRANGLER'
(Other definitions for wrangler that I've seen before include "Disputant - Cambridge mathematician" , "One arguing" , "Ranch livestock handler" , "Argumentative person - Cambridge mathematician" , "one is in charge of animals" .)