Formulas

Author

Mohammad Alkousa

Published

January 29, 2026

Basic Integration Rules

  • (for )
  • (for )
  • (for )

Exponential Integrals

  • (for )
  • (for )

Trigonometric Integrals

Hyperbolic Integrals

Inverse Trigonometric Integrals

  • (for )
  • (for )
  • (for )
  • (for )
  • (for )

Integration Techniques

Integration by Parts

Substitution Rule for Definite Integrals

Hermite-Ostrogradski Formula

Fundamental Theorem of Calculus

  • Part 1:
  • Part 2: where
  • Leibniz Rule:

Properties of Definite Integrals

  • Linearity:
  • Additivity:
  • Reversal:
  • Zero-width:
  • Even Function: (if )
  • Odd Function: (if )
  • Average Value:

Applications of Definite Integrals

  • Area Between Curves: (where )
  • Volume by Disk Method:
  • Volume by Washer Method:
  • Volume by Shell Method: (revolving about -axis)
  • Arc Length:
  • Parametric Arc Length:
  • Surface Area of Revolution: (about -axis)

Improper Integrals

  • Type 1 (Infinite Interval):
  • Type 2 (Discontinuity at ):
  • -Integral Test: converges if , diverges if

Trigonometric Identities

  • Power Reduction: ,
  • Product-to-Sum:
  • Pythagorean: , ,
  • Universal Substitution: gives:

Hyperbolic Identities

  • Power Reduction: ,
  • Pythagorean: ,
  • Definitions: , ,

Reduction Formulas

  • Sine Powers:
  • Cosine Powers:
  • Power-Exponential:

Functions of Several Variables

Partial Derivatives

  • Partial derivative w.r.t. :
  • Chain Rule (1 parameter):
  • Chain Rule (2 parameters):
  • Implicit Differentiation ():
  • Implicit Differentiation (): ,
  • Linearization:
  • Laplace Equation (Harmonic):

Directional Derivatives and Gradients

  • Gradient:
  • Directional Derivative: (where )
  • Maximum rate of increase: in direction

Extreme Values

  • Hessian / Discriminant:
  • Second Derivative Test: local max if ; local min if ; saddle if

Lagrange Multipliers

  • One constraint: and
  • Lagrangian:
  • Multiple constraints: and

Gradient Descent

  • Update rule:

Taylor’s Formula (Two Variables)

  • Quadratic approximation at : , where ,

Coordinate Systems

Polar and Cylindrical Coordinates

  • Polar ↔︎ Cartesian (2D): , ; ,
  • Cylindrical ↔︎ Cartesian (3D): , , ;

Spherical Coordinates

  • Spherical ↔︎ Cartesian: , , ;
  • Spherical ↔︎ Cylindrical: ,

3D Geometry

  • Distance formula:
  • Sphere:
  • Line (parametric): , ,
  • Plane: , normal

Double Integrals

Definition and Fubini’s Theorem

  • Double integral (definition):
  • Fubini (rectangle):
  • Fubini (vertically simple):
  • Fubini (horizontally simple):
  • Area:
  • Average value:

Change of Variables

  • Jacobian (2D):
  • Change of variables:
  • Polar coordinates (Jacobian ):
  • Area in polar:
  • Gaussian integral:

Triple Integrals

Definition and Fubini’s Theorem

  • Triple integral:
  • Fubini (general):
  • Volume:
  • Average value:

Change of Variables

  • Jacobian (3D): (3×3 determinant)
  • Change of variables:
  • Cylindrical coordinates (Jacobian ):
  • Spherical coordinates (Jacobian ):

Lagrange Multipliers

  • Lagrange condition (2D): , i.e., , ,
  • Lagrange function:
  • Lagrange condition (3D): , , ,

Taylor’s Formula for Multivariable Functions

  • Second degree Taylor polynomial at : , derivatives at
  • Maclaurin polynomial (degree 2): , derivatives at
  • General degree term: , where ,