How do you find the derivative of cos^2x? Calculus Differentiating Trigonometric Functions Derivative Rules for y=cos(x) and y=tan(x) 1 Answer Massimiliano Apr 16, 2015 In this way: y'=2cosx*(-sinx)=-2sinxcosx. 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 1670 views around the world You can reuse this answer Creative Commons License