For a real-valued function <math>f(x)</math> of one variable, the derivative of <math>f</math> corresponds to the [[slope]] of the tangent line to the graph of ''f'' at ''x''. | For a real-valued function <math>f(x)</math> of one variable, the derivative of <math>f</math> corresponds to the [[slope]] of the tangent line to the graph of ''f'' at ''x''. |