What is derivative of 1/cosx? Calculus Differentiating Trigonometric Functions Derivative Rules for y=cos(x) and y=tan(x) 1 Answer Daniel L. May 10, 2015 #(1/cosx)'=tanx/cosx# Proof: #(1/cosx)'=(1'*cosx-1*cosx')/(cos^2x)=(-1*(-sinx))/(cos^2x)=sinx/cos^2x=tanx/cosx# Answer link Related questions What is the derivative of #y=cos(x)# ? What is the derivative of #y=tan(x)# ? How do you find the 108th derivative of #y=cos(x)# ? How do you find the derivative of #y=cos(x)# from first principle? How do you find the derivative of #y=cos(x^2)# ? How do you find the derivative of #y=e^x cos(x)# ? How do you find the derivative of #y=x^cos(x)#? How do you find the second derivative of #y=cos(x^2)# ? How do you find the 50th derivative of #y=cos(x)# ? How do you find the derivative of #y=cos(x^2)# ? See all questions in Derivative Rules for y=cos(x) and y=tan(x) Impact of this question 47255 views around the world You can reuse this answer Creative Commons License