Differentiate `(tan x-(1)/(3secx))` with respect to 'x'.

Explanation

`(d)/(dx)(tan x-(1)/(3secx))`
`=(d)/(dx)(tan x-(1)/(3)cos x)`
`=(d)/(dx)(tan x)-(1)/(3)(d)/(dx)(cos x)`
`=(sec^(2)x+(1)/(3)sinx)`.