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Derivatives Differential Calculus

Reference data and engineering information about derivatives differential calculus for mathematics applications.

derivativesdifferentialcalculus

Overview

Engineering reference data for Derivatives Differential Calculus in mathematics.

Key Formulas

Quadratic Formula

x=b±b24ac2ax = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}

Roots of ax² + bx + c = 0.

Pythagorean Theorem

c2=a2+b2c^2 = a^2 + b^2

Right triangle relationship.

Circle Area

A=πr2A = \pi r^2

Area of a circle.

Logarithm

logb(x)=ln(x)ln(b)\log_b(x) = \frac{\ln(x)}{\ln(b)}

Change of base formula.

Variables

SymbolDescriptionUnit
π\piPi3.14159...
eeEuler's number2.71828...
19 rows
Common Derivative Rules and Formulas
Expression
Derivative
y = xⁿdy/dx = n xⁿ⁻¹
y = a xⁿdy/dx = a n xⁿ⁻¹
f(x) = a xⁿf'(x) = a n xⁿ⁻¹
y = eˣdy/dx = eˣ
y = eᵃˣdy/dx = a eᵃˣ
y = aˣdy/dx = aˣ ln(a)
y = ln(x)dy/dx = 1 / x
y = sin(Θ)dy/dΘ = cos(Θ)
y = cos(Θ)dy/dΘ = -sin(Θ)
y = tan(Θ)dy/dΘ = sec²(Θ)
y = cot(Θ)dy/dΘ = cosec²(Θ)
y = sec(Θ)dy/dΘ = tan(Θ) sec(Θ) = sin(Θ) / cos²(Θ)
y = cosec(Θ)dy/dΘ = -cot(Θ) cosec(Θ) = -cos(Θ) / sin²(Θ)
y = sin⁻¹(x / a)dy/dx = 1 / √(a² - x²)
y = cos⁻¹(x / a)dy/dx = -1 / √(a² - x²)
y = tan⁻¹(x / a)dy/dx = a / (a² + x²)
y = cot⁻¹(x / a)dy/dx = -a / (a² + x²)
y = sec⁻¹(x / a)dy/dx = a / (x√(x² - a²))
y = cosec⁻¹(x / a)dy/dx = -a / (x√(x² - a²))

Source: engineeringtoolbox.com

Key Derivative Rules Explained

This section breaks down the fundamental rules for finding derivatives, as summarized in the table above.

Power Rule

For a function y=xny = x^n, the derivative is dy/dx=nxn1dy/dx = n x^{n-1}. This rule also applies when multiplied by a constant, such as y=axny = a x^n, giving dy/dx=anxn1dy/dx = a n x^{n-1}.

Exponential & Logarithmic Rules

  • The derivative of the natural exponential function is itself: d/dx(ex)=exd/dx (e^x) = e^x.
  • For a general exponential function y=axy = a^x, the derivative involves the natural logarithm: dy/dx=axln(a)dy/dx = a^x \ln(a).
  • The derivative of the natural logarithm is: d/dx(lnx)=1/xd/dx (\ln x) = 1/x.

Trigonometric Function Derivatives

The derivatives of the basic trigonometric functions are:

  • ddΘsin(Θ)=cos(Θ)\frac{d}{d\Theta} \sin(\Theta) = \cos(\Theta)
  • ddΘcos(Θ)=sin(Θ)\frac{d}{d\Theta} \cos(\Theta) = -\sin(\Theta)
  • ddΘtan(Θ)=sec2(Θ)\frac{d}{d\Theta} \tan(\Theta) = \sec^2(\Theta)

Their reciprocals (cosecant, secant, cotangent) have derivatives that can be expressed in multiple forms, as shown in the table.

Inverse Trigonometric Function Derivatives

The derivatives of the inverse trigonometric functions yield algebraic expressions involving square roots and rational functions, which are essential for integration. For example:

  • ddxsin1(xa)=1a2x2\frac{d}{dx} \sin^{-1}\left(\frac{x}{a}\right) = \frac{1}{\sqrt{a^2 - x^2}}
  • ddxtan1(xa)=aa2+x2\frac{d}{dx} \tan^{-1}\left(\frac{x}{a}\right) = \frac{a}{a^2 + x^2}

References