Calculus

Essential formulas and concepts in calculus

Definition of Derivative

\(f'(x) = \displaystyle \lim_{h \to 0} \frac{f(x+h) - f(x)}{h}\)

Variables:

  • \(f(x) is a function, f'(x) is its derivative. h is an increment in x (approaching 0 in the limit).\)

Description/Usage:

Defines the derivative as the instantaneous rate of change or slope of the function \(f(x)\) at point \(x\). Graphically, it’s the slope of the tangent line to \(y=f(x)\) at \(x\).

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Power Rule (for derivatives)

\(\displaystyle \frac{d}{dx}\big(x^n\big) = n x^{n-1}\)

Variables:

  • \(n is a constant exponent, x is the variable.\)

Description/Usage:

Provides a quick way to differentiate monomials. For example, if \(f(x)=x^5\), then \(f'(x)=5x^4\). This rule is fundamental for polynomial differentiation.

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Indefinite Integral (Power Rule)

\(\displaystyle \int x^n\,dx = \frac{x^{n+1}}{n+1} + C \qquad(n \neq -1)\)

Variables:

  • \(n is a constant exponent (not -1); C is the constant of integration (since antiderivatives are determined up to an additive constant).\)

Description/Usage:

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Integration by Parts

\(\displaystyle \int u\,dv = uv - \int v\,du\)

Variables:

  • \(u and v are functions of x such that du and dv are their differentials (derivatives times dx). Often one sets u=f(x) and dv = g(x)dx.\)

Description/Usage:

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