Laboratory Project in Sec.3.10, Calculus by Stewart Chinese version: 泰勒級數 The tangent line approximation is the best first-degree (linear) approximation to near because and have the same rate of change (derivative) at . For a better approximation than a linear one, let’s try a second-degree (quadratic) approximation . In other words, we approximate a curve by a parabola instead of a straight