How do you find the points where the graph of the function y=tan(x)-x has horizontal tangents? Calculus Derivatives Tangent Line to a Curve 1 Answer Alberto P. Oct 26, 2016 x=kpi; k in ZZ Explanation: f^'(x)=1/cos^2x-1 f^'(x)=0 when cos^2x=1 or cosx=+-1 Answer link Related questions How do you find the equation of a tangent line to a curve? How do you find the slope of the tangent line to a curve at a point? How do you find the tangent line to the curve y=x^3-9x at the point where x=1? How do you know if a line is tangent to a curve? How do you show a line is a tangent to a curve? How do you find the Tangent line to a curve by implicit differentiation? What is the slope of a line tangent to the curve 3y^2-2x^2=1? How does tangent slope relate to the slope of a line? What is the slope of a horizontal tangent line? How do you find the slope of a tangent line using secant lines? See all questions in Tangent Line to a Curve Impact of this question 2100 views around the world You can reuse this answer Creative Commons License