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一変数の微積分
微分
01微分係数とは何か:接線の傾きとして定義する02割線から接線へ:極限による微分係数の定義031/x の導関数:先に約分、極限はそのあと041/x の接線と、面積がいつも2になる三角形05微分の記法とべき関数の微分公式問題セット0/10問題セット20/10MIT 問題セット0/3
01The Derivative as an Instantaneous Rate of Change02Rates of Change Without Time: Gradient and Sensitivity03Easy Limits, 0/0, and One-Sided Limits04Continuity, Jumps, and Removable Discontinuities05Infinite Discontinuities: 1/x and Its Derivative06Differentiable Implies Continuous問題セット0/10問題セット20/10
01Two Kinds of Formula, and the Derivative of Sine02The Derivative of Cosine, and Two Limits at Zero03Bow and Bowstring: Proving the Two Trig Limits04Why the Trig Derivatives Hold Only in Radians05A Geometric Proof: Sine as a Height on the Circle06Finishing the Proof, and the Product and Quotient Rules問題セット0/10問題セット20/10MIT 問題セット0/1
01Proving the Product Rule: Change One Factor at a Time02The Quotient Rule, and the Power Rule for Negative Exponents03The Chain Rule: Differentiating a Function of a Function04Higher Derivatives: The Sine Cycle and Three Notations05The nth Derivative of xⁿ Is n Factorial, by Induction問題セット0/10問題セット20/10MIT 問題セット0/2
01The Power Rule for Rational Exponents02The Slope of a Circle, Two Ways03Implicit Differentiation of a Quartic Curve04Inverse Functions and the Reflection Across y = x05Derivatives of the Arctangent and Arcsine問題セット0/10問題セット20/10MIT 問題セット0/1
01The Derivative of aˣ and the Mystery Number M(a)02Defining e by Slope One, and the Derivative of ln x03M(a) = ln a: Differentiating aˣ and xˣ04Why (1 + 1/n)ⁿ Approaches e問題セット0/10問題セット20/10MIT 問題セット0/1
微分の応用
01Linear Approximation: A Curve Is Its Tangent Line02Five Linear Approximations at Zero03Combining Approximations, from Algebra to GPS Clocks04Quadratic Approximation: The Best-Fit Parabola問題セット0/10問題セット20/10MIT 問題セット0/1
01Linear Approximation as a Proportionality Rule02Quadratic Approximation: Why the ½, and Products03Curve Sketching: The Sign of f′ and Critical Points04Curve Sketching: Ends, Concavity and Inflection問題セット0/10問題セット20/10MIT 問題セット0/1
01Sketching Without Critical Points: (x+1)/(x+2)02A Five-Step Curve-Sketching Scheme, Applied to x / ln x03x / ln x: Inflection Point and Where Max and Min Can Occur問題セット0/10問題セット20/10
01Two Squares From One Wire: The Critical Point Gives the Least Area02The Open Box of Fixed Volume: Least Material When x = 2y03Related Rates: The Police Radar and the Conical Tank問題セット0/10問題セット20/10MIT 問題セット0/4
01The Hanging Ring: Why the String Makes Equal Angles02Newton's Method: Tangent Lines That Find the Square Root of Five03Why Newton's Method Doubles Its Digits, and How It Fails04The Mean Value Theorem: Somewhere You Hit Your Average Speed05Positive Derivative Means Increasing: Proving eˣ Exceeds 1 + x問題セット0/10問題セット20/10MIT 問題セット0/2
積分
01Differentials: dy = f′(x) dx and the Cube Root of 64.102Antiderivatives Differ Only by a Constant03Integration by Substitution and Advanced Guessing問題セット0/10問題セット20/10MIT 問題セット0/1
01Separation of Variables: dy/dx = −xy and the Bell Curve02General Solutions: Signs, Constants and Initial Conditions03Orthogonal Trajectories: Parabolas and Crossing Ellipses問題セット0/10問題セット20/10MIT 問題セット0/1
01The Definite Integral: Area as a Limit of Rectangle Sums02Area Under y = x²: Squeezing the Sum of Squares03Sigma Notation and the Area Pattern: b, b²/2, b³/304Riemann Sums: the Definite Integral and a Year of Loans問題セット0/10問題セット20/10MIT 問題セット0/1
01The Fundamental Theorem of Calculus: Area in One Line02Net Change and Signed Area: Integrating Velocity03Six Rules for Definite Integrals and Bounds on eᵇ04Substitution in Definite Integrals: Change the Limits問題セット0/10問題セット20/10MIT 問題セット0/1

微分の記法とべき関数の微分公式

二項展開のたった2つの項が、x^n の差分商をどうやってべき関数の微分公式 n x^(n-1) に変えるのでしょうか。


読み込み中…

←前へ 1/x の接線と、面積がいつも2になる三角形次へ The Derivative as an Instantaneous Rate of Change →

まとめノート

    1. 1

      導関数の記法

      Δy=Δf\Delta y = \Delta fΔy=Δf なので2つの差分商が一致することを書き留め、f′(x0)f'(x_0)f′(x0​)、dfdx\frac{df}{dx}dxdf​、dydx\frac{dy}{dx}dxdy​、ddxf\frac{d}{dx}fdxd​f を同じ極限の呼び名として並べ、ライプニッツの形では基準点が省かれることも書き留めましょう。

    2. 2

      (x+Δx)n(x+\Delta x)^n(x+Δx)n に必要な二項展開

      (x+Δx)n=xn+n(Δx)xn−1+O((Δx)2)(x+\Delta x)^n = x^n + n(\Delta x)x^{n-1} + O((\Delta x)^2)(x+Δx)n=xn+n(Δx)xn−1+O((Δx)2) を書き、係数 nnn と高次のゴミがどこから来るのかを述べましょう。

    3. 3

      べき関数の微分公式 ddxxn=nxn−1\frac{d}{dx}x^n = nx^{n-1}dxd​xn=nxn−1

      xnx^nxn の差分商を作り、xnx^nxn と −xn-x^n−xn を打ち消し合わせ、Δx\Delta xΔx でわって nxn−1+O(Δx)nx^{n-1} + O(\Delta x)nxn−1+O(Δx) を得て、Δx→0\Delta x \to 0Δx→0 の極限をとりましょう。

    4. 4

      多項式への拡張

      公式が項ごとに使えることを述べ、ddx(x3+5x10)=3x2+50x9\frac{d}{dx}(x^3 + 5x^{10}) = 3x^2 + 50x^9dxd​(x3+5x10)=3x2+50x9 のような多項式を1つ微分しましょう。

    2回中1回目