What is the derivative of #cos(tan x)#? Calculus Basic Differentiation Rules Chain Rule 1 Answer Eddie Jun 23, 2016 # - sin (tan(x)) * sec^2 x# Explanation: #y = cos (tan x)# #= cos (p), \qquad p = tan(x)# so you chain rule it! #dy/(dp) = - sin (p)# #(dp)/dx = sec^2 x# # dy/dx = dy/(dp) * (dp)/dx # # = - sin (p) * sec^2 x# # = - sin (tan(x)) * sec^2 x# Answer link Related questions What is the Chain Rule for derivatives? How do you find the derivative of #y= 6cos(x^2)# ? How do you find the derivative of #y=6 cos(x^3+3)# ? How do you find the derivative of #y=e^(x^2)# ? How do you find the derivative of #y=ln(sin(x))# ? How do you find the derivative of #y=ln(e^x+3)# ? How do you find the derivative of #y=tan(5x)# ? How do you find the derivative of #y= (4x-x^2)^10# ? How do you find the derivative of #y= (x^2+3x+5)^(1/4)# ? How do you find the derivative of #y= ((1+x)/(1-x))^3# ? See all questions in Chain Rule Impact of this question 1083 views around the world You can reuse this answer Creative Commons License