BOOK OF MATHEMATICAL PROBLEMS. 

 1058. Find the general solution of the equations 



4>(x + y) =f(x)f(y) + <(*)</> (y) ; 



and hence prove that 2cosa;, 2v 1 sin a, can be expressed in 

 the form k' + k~' 9 k'-k~ x . 



1059. Prove that 



c - 1 x x* B, x 4 B^ x 6 



-- = -" + 



l -- 



