Question

What is the third derivative of tan x?

Answer 1

Third derivative would be 2[`2sec^2 x tan^2 x +sec^4x]`

If y= tan x

y' = `sec^2 x`

y''= 2secx secx tanx= `2sec^2 xtanx`

y ''' = 2`[2sec x sec x tan x tan x+ sec^2 x sec^2 x}`

= 2[`2sec^2 x tan^2 x +sec^4x]`