How do you differentiate #f(x)= tanx# twice using the quotient rule?
In order to start properly, let's just remember that
The quotient rule states that for a function
So, as for your function:
From trigonometric identities, we know that
To find the second derivative, use the chain rule, which states that for a function
Then, according to the chain rule:
Your interpretation of a final answer could vary.