Editing Tangent (section)

====Intuitive description====
Suppose that a curve is given as the graph of a [[function (mathematics)|function]], ''y'' = ''f''(''x''). To find the tangent line at the point ''p'' = (''a'', ''f''(''a'')), consider another nearby point ''q'' = (''a'' + ''h'', ''f''(''a'' + ''h'')) on the curve. The [[slope]] of the [[secant line]] passing through ''p'' and ''q'' is equal to the [[difference quotient]]

<math display="block">\frac{f(a+h)-f(a)}{h}.</math>

As the point ''q'' approaches ''p'', which corresponds to making ''h'' smaller and smaller, the difference quotient should approach a certain limiting value ''k'', which is the slope of the tangent line at the point ''p''. If ''k'' is known, the equation of the tangent line can be found in the point-slope form:

<math display="block"> y-f(a) = k(x-a).\,</math>