If #x = cos(3t)# and #y = sin^2(3t)#, how do you find dy/dx? Calculus Differentiating Trigonometric Functions Derivative Rules for y=cos(x) and y=tan(x) 1 Answer Massimiliano Apr 13, 2015 Since #sin^2x+cos^2x=1# Than #y=sin^2(3t)=1-cos^2(3t)=1-x^2#. So: #y'=-2x#. 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 4291 views around the world You can reuse this answer Creative Commons License