Question: what is the formula for slope of a tangent line?
Answer: The value of f '(x) at a given point is the slope of the tangent line at that point. Once the slope is known, finding the equation of the tangent line is a matter of using the point-slope formula: (y - y1) = (m(x - x1)). Differentiate the function f(x) in order to find the slope of the graph at a specified point.