No, it is an estimate of the slope of the tangent line (i.e., the instantaneous rate of change at a particular point). The OP evaluated the function in order to estimate the value of its derivative. A calculator
of h values smaller than that. In fact I start with h=0.1, and reduce each successive h by a factor of 10. The table below is generated with my hp calculator but I assume that a standard TI would give comparable results. The display gives me 9 decimal places, but internally the...