Calculus
What is Calculus?
The value that a function approaches as the input (or independent variable) approaches some specific value.
Key formula / rule: Derivative of a function (definition)
Key points
- Understand and apply the concepts of limits, continuity, and differentiability.
- Master various techniques of differentiation and integration.
- Apply calculus to solve problems involving rates of change, optimization, areas, volumes, and arc lengths.
- Comprehend and apply concepts of multiple integrals (double and triple).
Common exam trap
Incorrectly applying L'Hôpital's rule without verifying indeterminate forms.
Definitions
- Term
Limit
- Meaning
The value that a function approaches as the input (or independent variable) approaches some specific value.
- Term
Continuity
- Meaning
A function is continuous at a point if its limit exists at that point, the function is defined at that point, and the limit value equals the function's value at that point.
- Term
Derivative
- Meaning
The instantaneous rate of change of a function with respect to its independent variable, geometrically representing the slope of the tangent line to the function's graph at a given point.
- Term
Integral
- Meaning
A mathematical operation that represents the accumulation of quantities, often interpreted as the area under the curve of a function over a given interval.
- Term
Gradient
- Meaning
A vector field derived from a scalar field that indicates the direction of the greatest rate of increase of the scalar field and whose magnitude is that maximum rate of change.
- Term
Divergence
- Meaning
A scalar field that measures the magnitude of a vector field's source or sink at a given point, representing the net outward flux per unit volume.
- Term
Curl
- Meaning
A vector field that measures the infinitesimal rotation or 'circulation' of a vector field at a given point, indicating the axis and magnitude of rotation.
Learning objectives
Understand and apply the concepts of limits, continuity, and differentiability.
Master various techniques of differentiation and integration.
Apply calculus to solve problems involving rates of change, optimization, areas, volumes, and arc lengths.
Comprehend and apply concepts of multiple integrals (double and triple).
Understand and utilize vector calculus operators (gradient, divergence, curl) and fundamental integral theorems (Green's, Gauss's, Stokes's).
Formulae
- Name
Derivative of a function (definition)
- Note
Represents the instantaneous rate of change.
- Expression
f'(x) = lim (h→0) [f(x+h) - f(x)] / h
- Name
Chain Rule
- Note
Used for differentiating composite functions.
- Expression
d/dx [f(g(x))] = f'(g(x)) * g'(x)
- Name
Product Rule
- Note
Used for differentiating a product of two functions.
- Expression
d/dx [u(x)v(x)] = u'(x)v(x) + u(x)v'(x)
- Name
Quotient Rule
- Note
Used for differentiating a quotient of two functions.
- Expression
d/dx [u(x)/v(x)] = [u'(x)v(x) - u(x)v'(x)] / [v(x)]2
- Name
L'Hôpital's Rule
- Note
Applies to indeterminate forms of limits.
- Expression
If lim (x→c) f(x)/g(x) is 0/0 or ∞/∞, then lim (x→c) f(x)/g(x) = lim (x→c) f'(x)/g'(x)
- Name
Fundamental Theorem of Calculus (Part 2)
- Note
Connects differentiation and integration, used for definite integrals.
- Expression
∫ab f(x) dx = F(b) - F(a), where F'(x) = f(x)
- Name
Integration by Parts
- Note
Used for integrating products of functions.
- Expression
∫u dv = uv - ∫v du
- Name
Gradient of a scalar field φ
- Note
A vector pointing in the direction of the greatest rate of increase of φ.
- Expression
∇φ = (∂φ/∂x)i + (∂φ/∂y)j + (∂φ/∂z)k
- Name
Divergence of a vector field F
- Note
A scalar representing the outward flux density from a point.
- Expression
∇·F = (∂Fx/∂x) + (∂Fy/∂y) + (∂Fz/∂z)
- Name
Curl of a vector field F
- Note
A vector representing the rotational tendency of the field at a point.
- Expression
∇×F = (∂Fz/∂y - ∂Fy/∂z)i + (∂Fx/∂z - ∂Fz/∂x)j + (∂Fy/∂x - ∂Fx/∂y)k
- Name
Green's Theorem (in the plane)
- Note
Relates a line integral around a simple closed curve C to a double integral over the plane region R enclosed by C.
- Expression
∮C (P dx + Q dy) = ∫∫R (∂Q/∂x - ∂P/∂y) dA
- Name
Gauss's Divergence Theorem
- Note
Relates the flux of a vector field through a closed surface S to the divergence of the field in the volume V enclosed by S.
- Expression
∮S F·dS = ∫∫∫V (∇·F) dV
- Name
Stokes' Theorem
- Note
Relates the line integral of a vector field around a closed curve C to the surface integral of the curl of the field over any surface S bounded by C.
- Expression
∮C F·dr = ∫∫S (∇×F)·dS
Prerequisites
Basic Algebra (polynomials, functions, equations, inequalities)
Trigonometry (identities, functions, inverse functions)
Coordinate Geometry (lines, circles, conic sections)
Basic understanding of functions and their graphs
Common mistakes
Incorrectly applying L'Hôpital's rule without verifying indeterminate forms.
Errors in choosing appropriate integration techniques (e.g., substitution, integration by parts).
Forgetting the constant of integration for indefinite integrals.
Incorrectly setting up limits of integration for definite and multiple integrals.
Confusing scalar and vector operations in vector calculus (e.g., dot product vs. cross product).
Sign errors during differentiation or integration.
Not verifying the conditions for applying Mean Value Theorems or integral theorems.
Keywords
Limits
Continuity
Differentiability
Derivatives
Integrals
Definite Integral
Indefinite Integral
L'Hôpital's Rule
Maxima
Minima
Mean Value Theorem
Rolle's Theorem
Lagrange's Theorem
Multiple Integrals
Double Integral
Triple Integral
Vector Calculus
Gradient
Divergence
Curl
Green's Theorem
Gauss's Theorem
Stokes' Theorem
Optimization
Area
Volume
Flux
Circulation
Practice preview
Find the local minimum value of the function f(x) = x^3 - 3x + 2.…
medium
Evaluate the definite integral: integral (from 0 to pi/2) (cos(x)) dx…
medium
Evaluate the limit: lim (x->0) (sin(x)/x)…
easy
