What is the derivative of #f(x)=cos(pi/2-x)#? Calculus Differentiating Trigonometric Functions Derivative Rules for y=cos(x) and y=tan(x) 1 Answer Andrea S. Feb 22, 2017 #d/dx cos (pi/2-x) = cosx# Explanation: Using the trigonometric formula: #cos(alpha-beta) = cos alpha cos beta + sin alpha sin beta# we have: #cos (pi/2-x) = sinx# so: #d/dx cos (pi/2-x) = d/dx sinx = 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 5617 views around the world You can reuse this answer Creative Commons License