Question

http://prntscr.com/kk56cx

Answer 1

http://prntscr.com/kk56hs

Answer 2

the derivative of tan(x) is sec^2(x)
the derivative of sinh^(-1) is 1/sqrt(1+x^2)

so apply the chain rule to the function composition

take the derivative of sinh^(-1) of (tan(3x)) to be 1/sqrt(1+[tan3x]^2) * the derivative of tan(3x)

Answer 3

Thank you @Komaeda ^^^