IOE Entrance notes
IoeMathematics•Updated: 5/8/2026
📘 ENGINEERING / ENTRANCE MATHEMATICS NOTES
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1. SET, LOGIC AND FUNCTIONS
1.1 Set, Real Number System, Intervals, Absolute Value, Logic
Set
A set is a well-defined collection of objects.
Real Number System
The set of rational and irrational numbers together forms the real number system.
Types of Numbers
• Natural Numbers
• Whole Numbers
• Integers
• Rational Numbers
• Irrational Numbers
• Real Numbers
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Intervals
Interval Type Representation
Open Interval \((a,b)\)
Closed Interval \([a,b]\)
Half Open Interval \((a,b]\), \([a,b)\)
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Absolute Value
The absolute value represents distance from zero.
$$
|x| =
\begin{cases}
x, & x \geq 0 \\
-x, & x < 0
\end{cases}
$$
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Logic
Logic deals with truth values.
Connectives
Connective Symbol
AND (\land)
OR \(\lor\)
NOT \(\lnot\)
Implication \(\to\)
Biconditional \(\leftrightarrow\)
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Laws of Logic
Commutative Laws
$$p \lor q = q \lor p$$
$$p \land q = q \land p$$
De Morgan’s Laws
$$\lnot(p \lor q) = \lnot p \land \lnot q$$
$$\lnot(p \land q) = \lnot p \lor \lnot q$$
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1.2 FUNCTIONS
Function
A function maps each input to exactly one output.
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Types of Functions
Injective Function (One-One)
Different inputs have different outputs.
Surjective Function (Onto)
Every element in codomain has at least one pre-image.
Bijective Function
Both injective and surjective.
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Other Functions
• Algebraic Functions
• Trigonometric Functions
• Exponential Functions
• Logarithmic Functions
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Composite Function
$$(f \circ g)(x) = f(g(x))$$
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Inverse Function
$$f^{-1}(x)$$
If:
$$f(x) = y$$
then:
$$f^{-1}(y) = x$$
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2. ALGEBRA
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2.1 MATRICES AND DETERMINANTS
Matrix
A rectangular arrangement of numbers.
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Types of Matrices
• Row Matrix
• Column Matrix
• Square Matrix
• Identity Matrix
• Diagonal Matrix
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Determinant
$$
\begin{vmatrix}
a & b \\
c & d
\end{vmatrix}
= ad - bc
$$
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Inverse of Matrix
For matrix:
$$A =
\begin{bmatrix}
a & b \\
c & d
\end{bmatrix}
$$
Inverse:
$$
A^{-1} = \frac{1}{ad-bc}
\begin{bmatrix}
d & -b \\
-c & a
\end{bmatrix}
$$
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2.2 COMPLEX NUMBERS AND POLYNOMIAL EQUATIONS
Complex Number
$$z = a + ib$$
where:
• \(a\) = real part
• \(b\) = imaginary part
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Properties
$$i^2 = -1$$
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Polynomial Equation
General form:
$$a_n x^n + a_{n-1} x^{n-1} + \cdots + a_0 = 0$$
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2.3 SEQUENCE AND SERIES
Arithmetic Progression (AP)
$$a_n = a + (n-1)d$$
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Geometric Progression (GP)
$$a_n = ar^{n-1}$$
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PERMUTATION AND COMBINATION
Permutation
$$^n P_r = \frac{n!}{(n-r)!}$$
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Combination
$$^n C_r = \frac{n!}{r!(n-r)!}$$
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2.4 BINOMIAL THEOREM
Formula
$$
(a+b)^n = \sum_{k=0}^{n} \binom{n}{k} a^{n-k} b^k
$$
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Exponential Series
$$
e^x = 1 + x + \frac{x^2}{2!} + \frac{x^3}{3!} + \cdots
$$
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Logarithmic Series
$$
\log(1+x) = x - \frac{x^2}{2} + \frac{x^3}{3} - \cdots
$$
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3. TRIGONOMETRY
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3.1 TRIGONOMETRIC EQUATIONS
Basic Ratios
$$\sin\theta = \frac{\text{opposite}}{\text{hypotenuse}}$$
$$\cos\theta = \frac{\text{adjacent}}{\text{hypotenuse}}$$
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General Solution
For:
$$\sin x = 0$$
General solution:
$$x = n\pi$$
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3.2 INVERSE TRIGONOMETRIC FUNCTIONS
Principal Value
Function Principal Value
$$(\sin^{-1}x) ([-\pi/2,\pi/2])
(\cos^{-1}x) ([0,\pi])
(\tan^{-1}x) ((-\pi/2,\pi/2)) $$
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3.3 PROPERTIES OF TRIANGLES
Important Centers
• In-centre
• Circum-centre
• Ortho-centre
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Law of Sines
$$
\frac{a}{\sin A} = \frac{b}{\sin B} = \frac{c}{\sin C}
$$
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4. COORDINATE GEOMETRY
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4.1 STRAIGHT LINES
Slope Formula
$$m = \frac{y_2 - y_1}{x_2 - x_1}$$
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Equation of Line
$$y = mx + c$$
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4.2 CIRCLES
Standard Equation
$$x^2 + y^2 + 2gx + 2fy + c = 0$$
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Tangent Equation
$$xx_1 + yy_1 = r^2$$
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4.3 CONIC SECTIONS
Parabola
$$y^2 = 4ax$$
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Ellipse
$$\frac{x^2}{a^2} + \frac{y^2}{b^2} = 1$$
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Hyperbola
$$\frac{x^2}{a^2} - \frac{y^2}{b^2} = 1$$
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4.4 COORDINATES IN SPACE
Distance Formula
$$
d = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2 + (z_2 - z_1)^2}
$$
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5. CALCULUS
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5.1 LIMIT AND CONTINUITY
Limit
$$\lim_{x \to a} f(x)$$
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L’Hospital’s Rule
If:
$$\frac{0}{0} \text{ or } \frac{\infty}{\infty}$$
then:
$$
\lim \frac{f(x)}{g(x)} = \lim \frac{f'(x)}{g'(x)}
$$
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5.2 DERIVATIVES
Basic Formula
$$
\frac{d}{dx}(x^n) = nx^{n-1}
$$
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Applications
• Tangent and Normal
• Rate of Change
• Maxima and Minima
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5.3 INTEGRATION
Standard Integral
$$
\int x^n \, dx = \frac{x^{n+1}}{n+1} + C
$$
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Applications
• Area under curve
• Area between curves
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5.4 DIFFERENTIAL EQUATIONS
Definition
An equation involving derivatives.
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Types
• Variable Separable
• Homogeneous
• Linear Differential Equation
• Exact Differential Equation
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6. VECTORS AND THEIR PRODUCTS
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6.1 VECTORS
Magnitude
$$
|\vec{a}| = \sqrt{x^2 + y^2 + z^2}
$$
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Types
• Linearly Dependent
• Linearly Independent
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6.2 PRODUCT OF VECTORS
Scalar Product
$$
\vec{a} \cdot \vec{b} = |\vec{a}| |\vec{b}| \cos\theta
$$
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Vector Product
$$
\vec{a} \times \vec{b}
$$
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Scalar Triple Product
$$
\vec{a} \cdot (\vec{b} \times \vec{c})
$$
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7. STATISTICS AND PROBABILITY
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7.1 MEASURES OF LOCATION
Mean
$$
\bar{x} = \frac{\sum x}{n}
$$
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Dispersion
• Variance
• Standard Deviation
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7.2 CORRELATION AND REGRESSION
Correlation Coefficient
$$
r = \frac{\sum (x - \bar{x})(y - \bar{y})}{\sqrt{\sum (x - \bar{x})^2 \sum (y - \bar{y})^2}}
$$
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7.3 PROBABILITY
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Probability
Probability measures the chance of occurrence of an event.
Probability Formula
$$
P(A) = \frac{\text{Favorable Outcomes}}{\text{Total Outcomes}}
$$
Important Points
• Probability always lies between 0 and 1
• Probability of impossible event = 0
• Probability of certain event = 1
Example
If a coin is tossed:
$$
P(\text{Head}) = \frac{1}{2}
$$
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Bayes’ Theorem
Formula
$$
P(A \mid B) = \frac{P(B \mid A) \cdot P(A)}{P(B)}
$$
Where
• \(P(A \mid B)\) = Probability of A given B
• \(P(B \mid A)\) = Probability of B given A
• \(P(A)\) = Probability of A
• \(P(B)\) = Probability of B
Applications
• Medical diagnosis
• Statistical prediction
• Machine learning
• Data analysis
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Binomial Distribution
Formula
$$
P(X = r) = \binom{n}{r} p^r q^{\,n-r}
$$
Where
• \(n\) = Total number of trials
• \(r\) = Number of successful outcomes
• \(p\) = Probability of success
• \(q = 1-p\) = Probability of failure
Example
For tossing a coin 3 times:
$$
P(X = 2) = \binom{3}{2} \left(\frac{1}{2}\right)^2 \left(\frac{1}{2}\right)^1
$$
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EXAM TIPS
• Practice formulas daily
• Revise derivations regularly
• Solve previous year questions
• Focus on weak chapters
• Make short revision notes
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QUICK REVISION FORMULAS
Arithmetic Progression (AP)
$$a_n = a + (n-1)d$$
Geometric Progression (GP)
$$a_n = ar^{n-1}$$
Derivative Formula
$$\frac{d}{dx}(x^n) = nx^{n-1}$$
Integration Formula
$$\int x^n \, dx = \frac{x^{n+1}}{n+1} + C$$
Probability Formula
$$P(A) = \frac{\text{Favorable Outcomes}}{\text{Total Outcomes}}$$
Binomial Theorem
$$(a+b)^n = \sum_{k=0}^{n} \binom{n}{k} a^{n-k} b^k$$