Rationalised 2023-24
CONTINUITY AND DIFFERENTIABILITY
141
(ii)
Let y = log7 (log x) = log (log )
log7
x  (by change of base formula) The function is defined for all real numbers x > 1 Therefore
dy
dx  =
1
(log (log ))
log7
d
x
dx
=
1
1
(log )
log7 log
d
x
x dx
⋅
=
1
xlog7 log
x
Example 40 Differentiate the following w r