How do you find all points on the graph of #f(x)=sin^2x# at which the tangent line is horizontal? Calculus Differentiating Trigonometric Functions Derivative Rules for y=cos(x) and y=tan(x) 1 Answer Alberto P. Nov 8, 2016 graph{(sinx)^2 [-10, 10, -5, 5]} #kpi/2 \ \ \ ;\ \ \ kinZZ# Explanation: #f^'(x)=2sinxcosx=sin2x# #sin(2x)=0\ \ \ # when #\ \ \ \2x=kpi\ \ \ ; \ \ \ k in ZZ# 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 1778 views around the world You can reuse this answer Creative Commons License