الانتقال إلى المحتوى
The Lumenary
بداية المرحلة الجامعيةAnalysisالدرس متاح

Multivariable and vector calculus

Calculus III: partial derivatives, the derivative as a linear map, optimisation with Lagrange multipliers, multiple integrals and change of variables, line and surface integrals, and the theorems of Green, Stokes and Gauss.

math.analysis.multivariable-calculus

يعتمد على

عدد المتطلبات السابقة الإلزامية (حتى الأساس): 36

ستتعلّم

  • Compute partial and directional derivatives, gradients and Jacobian matrices.
  • Solve constrained optimisation problems with Lagrange multipliers.
  • Evaluate multiple, line and surface integrals and apply Green's theorem, Stokes's theorem and the divergence theorem.

تعريف

  • The derivative of f : ℝⁿ → ℝᵐ at a is the linear map Df(a) such that f(a + h) = f(a) + Df(a)h + o(|h|) as h → 0.
  • The gradient ∇f of a real-valued function collects its partial derivatives.

مبرهنة

  • Chain rule: D(g ∘ f)(a) = Dg(f(a)) ∘ Df(a).
  • Change of variables in multiple integrals uses the absolute value of the Jacobian determinant.
  • Divergence theorem: the flux of F out of a bounded region V with smooth boundary equals ∭_V div F dV.
  • If all partial derivatives of f exist and are continuous near a, then f is differentiable at a.

مفاهيم خاطئة شائعة

  • Thinking the existence of partial derivatives implies differentiability.
  • Forgetting the Jacobian factor when changing variables.

يقود إلى

اكتشافات اختيارية

  • Functors The chain rule says that taking derivatives respects composition; in categorical language, differentiation at a point is functorial.

مسارات التعلّم

قراءات إضافية

  • John H. Hubbard and Barbara Burke Hubbard, Vector Calculus, Linear Algebra, and Differential Forms