Math Help - Function

1. Function

Knowing that $f(x)=tg^2(3x+1)$, the value of $f''(\frac{-1}{3})$ is ?

2. Originally Posted by Apprentice123
Knowing that $f(x)=tg^2(3x+1)$, the value of $f''(\frac{-1}{3})$ is ?
Since f is a linear function the second derivative is zero for all x.