linguistic:voice_change, quality:corruption
Linear approximations

Linear approximations are used to replace complicated functions with linear functions that are almost the same. Given a differentiable function f (x, y) with real values, one can approximate f (x, y) for (x, y) close to (a, b) by the formula

The right-hand side is the equation of the plane tangent to the graph of z = f (x, y) at (a, b).