Calculus
What is Calculus?
The value that a function or sequence 'approaches' as the input or index approaches some value.
Key formula / rule: Limit Definition
Key points
- Understand the concept of a limit and how to evaluate it.
- Define and check for continuity of a function at a point and over an interval.
- Define and check for differentiability of a function at a point.
- Relate continuity and differentiability.
Common exam trap
Confusing limits with function values.
Definitions
- Term
Limit
- Meaning
The value that a function or sequence 'approaches' as the input or index approaches some value.
- Term
Continuity
- Meaning
A function is continuous at a point if its graph can be drawn through the point without lifting the pen; formally, if the limit exists, the function is defined at the point, and the limit equals the function's value.
- Term
Differentiability
- Meaning
A function is differentiable at a point if its derivative exists at that point, meaning the graph has a unique, non-vertical tangent line.
- Term
Derivative
- Meaning
The instantaneous rate of change of a function with respect to a variable; geometrically, the slope of the tangent line to the function's graph.
Learning objectives
Understand the concept of a limit and how to evaluate it.
Define and check for continuity of a function at a point and over an interval.
Define and check for differentiability of a function at a point.
Relate continuity and differentiability.
Interpret the derivative as a rate of change and slope.
Formulae
- Name
Limit Definition
- Note
f(x) approaches L as x approaches c.
- Expression
limx→c f(x) = L
- Name
Continuity Condition
- Note
Requires f(c) to be defined and the limit to exist and be equal to f(c).
- Expression
limx→c f(x) = f(c)
- Name
Derivative Definition (Limit Form)
- Note
Represents the instantaneous rate of change at c.
- Expression
f'(c) = limh→0 \frac{f(c+h) - f(c)}{h}
- Name
L'Hôpital's Rule
- Note
Used for indeterminate forms.
- Expression
\limx\to c \frac{f(x)}{g(x)} = \limx\to c \frac{f'(x)}{g'(x)} \quad \text{(if form is } \frac{0}{0} \text{ or } \frac{\∞}{\∞})
Prerequisites
Basic algebra (functions, equations, inequalities).
Understanding of graphs of functions.
Familiarity with basic trigonometric and exponential functions.
Common mistakes
Confusing limits with function values.
Assuming continuity implies differentiability.
Incorrectly applying limit rules, especially with indeterminate forms (0/0, ∞/∞).
Errors in algebraic manipulation when evaluating limits.
Keywords
Limit
Continuity
Differentiability
Derivative
Rate of Change
Tangent Line
L'Hôpital's Rule
Indeterminate Forms
Practice preview
Evaluate the indefinite integral: integral (2x + 3) dx…
easy
If z = x^2y + 3xy^4, find the partial derivative of z with respect to x, denoted as partial z / partial x.…
medium
For the function f(x) = x^2 on the interval [0, 2], find a value 'c' that satisfies the Mean Value Theorem.…
medium
