The second order derivative of f(x) is denoted by f ″(x) It is also
denoted by D2 y or y″ or y2 if y = f(x) We remark that higher order derivatives may be
defined similarly Rationalised 2023-24
 MATHEMATICS
138
Example 35 Find 
2
2
d y
dx
, if  y = x3 + tan x