Question

If y = log (sec x + tan x), find `dy/dx`.

Answer 1

∵ y = log (sec x + tan x)

∴ `dy/dx = 1/(secx + tanx) xx d/dx (secx + tanx)`

= `(secx tanx + sec^2x)/(secx + tanx)`

= `(secx (tanx + secx))/((secx + tanx))`

= sec x