What is the derivative of #y=cos(x)# ? Calculus Differentiating Trigonometric Functions Derivative Rules for y=cos(x) and y=tan(x) 1 Answer Calculus V. Jul 24, 2014 #dy/dx=(cos x)'=-sin x#. See derivatives of trig functions for details. Answer link Related questions 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)# ? How do you find the derivative of #y=cos(cosx)# ? See all questions in Derivative Rules for y=cos(x) and y=tan(x) Impact of this question 7280 views around the world You can reuse this answer Creative Commons License