Most functions are not linear, and their graphs are not straight lines. For most functions the computation of the derivative is not as simple as in the previous example. {{CMD_194}} Let {{MATH_195}}. Find the slope of the tangent line to the curve {{MATH_196}} at the point {{MATH_197}}. {{CMD_198}} Finding the slope of the tangent line at the point {{MATH_199}} means finding {{MATH_200}} {{MATH_201}} This limit gives us the instantaneous rate of change of {{MATH_202}} at {{MATH_203}}, which was computed in our first example! Therefore, the slope of the tangent line is {{MATH_204}} {{CMD_205}} {{CMD_206}} We can confirm our results by looking at the graph of {{MATH_207}} and the line {{MATH_208}}. {{CMD_209}}{{ENV_210}}{{CMD_211}} {{CMD_212}} {{CMD_213}}