Complete Exhaustive Mathematics Formulas Repository (Class 6 to 12)
Chapter 1: Knowing Our Numbers
Indian System: Ones, Tens, Hundreds, Thousands, Ten Thousand, Lakh, Ten Lakh, Crore, Ten Crore.
International System: Ones, Tens, Hundreds, Thousands, Ten Thousand, Hundred Thousand, Million, Ten Million, Hundred Million, Billion.
Estimation / Rounding off: Nearest tens (look at digits < 5 or >= 5), Nearest hundreds, Nearest thousands.
Chapter 2: Whole Numbers
Predecessor: Number - 1 (except for 0 in whole numbers).
Successor: Number + 1.
Closure Property: Whole numbers are closed under addition and multiplication (a + b and a x b are whole numbers).
Commutative Property: a + b = b + a and a x b = b x a.
Associative Property: (a + b) + c = a + (b + c) and (a x b) x c = a x (b x c).
Distributive Property: a x (b + c) = (a x b) + (a x c).
Chapter 3: Playing with Numbers
Factors: Exact divisor of a number. Every number is a factor of itself; 1 is a factor of every number.
Multiples: Number multiplied by integers. Every multiple is greater than or equal to the number.
Divisibility Rules:
By 2 (last digit even),
By 3 (sum of digits divisible by 3),
By 4 (last two digits divisible by 4),
By 5 (ends in 0 or 5),
By 6 (divisible by both 2 and 3),
By 8 (last three digits divisible by 8),
By 9 (sum of digits divisible by 9),
By 10 (ends in 0),
By 11 (difference of sum of alternating digits is 0 or multiple of 11).
Relationship: HCF x LCM = Product of two given numbers.
Chapter 4: Basic Geometrical Ideas
Line: Extends indefinitely in both directions (no endpoints).
Line Segment: Part of a line with two definite endpoints.
Ray: Part of a line with one starting point and extending endlessly in one direction.
Polygon: Simple closed curve made entirely of line segments (Triangle = 3, Quadrilateral = 4, Pentagon = 5, Hexagon = 6).
Chapter 5: Understanding Elementary Shapes
Types of Angles: Acute (< 90 degrees), Right (= 90 degrees), Obtuse (90 to 180 degrees), Straight (= 180 degrees), Reflex (> 180 and < 360 degrees), Complete (= 360 degrees).
Perpendicular Lines: Lines intersecting at 90 degrees.
Triangle Classification: By sides (Scalene, Isosceles, Equilateral); By angles (Acute-angled, Right-angled, Obtuse-angled).
Chapter 6: Integers
Addition of Integers: Same signs add and keep sign; Opposite signs subtract and take the sign of the larger absolute value.
Subtraction of Integers: a - b = a + (additive inverse of b).
Chapter 7: Fractions
Fraction Form: Numerator / Denominator.
Addition/Subtraction (Like): (a +- b) / c.
Addition/Subtraction (Unlike): Convert denominators to LCM first, then add/subtract.
Multiplication: (Numerator x Numerator) / (Denominator x Denominator).
Division: Fraction A / Fraction B = Fraction A x Reciprocal of Fraction B.
Chapter 8: Decimals
Place Value in Decimals: Tenths (1/10), Hundredths (1/100), Thousandths (1/1000).
Standard Form: ax + by + c = 0 (where a, b, c are real numbers and a, b are not both zero).
Solution Set: Infinite number of solutions represented as a straight line on the Cartesian plane.
Chapter 5: Introduction to Euclid's Geometry
Axioms & Postulates: Self-evident assumptions (e.g., Postulate 5: Parallel postulate regarding lines intersecting when interior angle sum is less than 180 degrees).
Standard Form: ax^2 + bx + c = 0 (where a not equal to 0).
Quadratic Formula (Sridharacharya Formula): x = (-b +- sqrt(b^2 - 4ac)) / (2a)
Discriminant (D): D = b^2 - 4ac
Nature of Roots:
If D > 0 (Two distinct real roots),
If D = 0 (Two equal real roots, x = -b/2a),
If D < 0 (No real roots / complex roots).
Chapter 5: Arithmetic Progressions (AP)
General Form of AP: a, a+d, a+2d, a+3d, ...
Nth Term of AP: a_n = a + (n - 1)d
Sum of First n Terms: S_n = (n/2) x [2a + (n - 1)d] or S_n = (n/2) x (a + l) where l is the last term.
Chapter 6: Triangles
Thales Theorem (Basic Proportionality Theorem): If a line is drawn parallel to one side of a triangle intersecting the other two sides, then it divides the two sides in the same ratio.
Similarity Criteria: AAA (Angle-Angle-Angle), SSS (Side-Side-Side), SAS (Side-Angle-Side).
Area Ratio Theorem: Ratio of areas of two similar triangles is equal to the square of the ratio of their corresponding sides.
Pythagoras Theorem: In a right triangle, square of hypotenuse equals sum of squares of other two sides.
Line of Sight & Angles: Angle of Elevation (looking up from horizontal), Angle of Depression (looking down from horizontal).
Chapter 10: Circles
Tangent Property: Tangent at any point of a circle is perpendicular to the radius through the point of contact.
Tangent Length Theorem: Lengths of tangents drawn from an external point to a circle are equal.
Chapter 11: Areas Related to Circles
Area of Circle: pi x r^2
Circumference of Circle: 2 x pi x r
Area of Sector: (theta / 360) x pi x r^2
Length of Arc: (theta / 360) x 2 x pi x r
Area of Segment: Area of corresponding sector - Area of corresponding triangle.
Chapter 12: Surface Areas and Volumes
Frustum of Cone Surface Areas: CSA = pi x (r1 + r2) x l (where slant height l = sqrt(h^2 + (r1 - r2)^2)), TSA = pi x (r1 + r2) x l + pi x r1^2 + pi x r2^2.
Volume of Frustum: (1/3) x pi x h x (r1^2 + r2^2 + (r1 x r2)).
Chapter 13: Statistics
Mean (Assumed Mean Method): Mean = a + (sum(f_i x d_i) / sum(f_i)) where d_i = x_i - a.
Mean (Step-Deviation Method): Mean = a + (sum(f_i x u_i) / sum(f_i)) x h.
Median Formula: Median = L + [ ((n/2 - cf) / f) ] x h
Mode Formula: Mode = L + [ ((f1 - f0) / (2f1 - f0 - f2)) ] x h
Empirical Relationship: 3 Median = Mode + 2 Mean.
Chapter 14: Probability
Classical Probability: P(E) = Number of outcomes favorable to E / Total number of possible outcomes of the experiment.
Complementary Event: P(E) + P(not E) = 1.
Chapter 1: Sets
Set Operations: Union (A union B), Intersection (A intersection B), Difference (A - B).
De Morgan's Laws: (A union B)' = A' intersection B'; (A intersection B)' = A' union B'.
Cardinality Formula: n(A union B) = n(A) + n(B) - n(A intersection B).
Three Set Cardinality: n(A union B union C) = n(A) + n(B) + n(C) - n(A int B) - n(B int C) - n(C int A) + n(A int B int C).
Chapter 2: Relations and Functions
Cartesian Product: A x B = {(a, b) : a in A and b in B}. If n(A)=p, n(B)=q, then n(A x B) = p x q.
Relation: Subset of A x B. Domain, Codomain, and Range.
Functions: Special relations where every element in domain has a unique image in codomain.
Chapter 3: Trigonometric Functions
Degree-Radian Conversion: Radian = Degree x (pi / 180).
Compound Angle Formulas:
sin(x + y) = sin x cos y + cos x sin y,
sin(x - y) = sin x cos y - cos x sin y,
cos(x + y) = cos x cos y - sin x sin y,
cos(x - y) = cos x cos y + sin x sin y.
Transformation Formulas:
cos x + cos y = 2 cos((x+y)/2) cos((x-y)/2),
sin x + sin y = 2 sin((x+y)/2) cos((x-y)/2).
Sine Rule & Cosine Rule (Properties of Triangles): a/sin A = b/sin B = c/sin C and cos A = (b^2 + c^2 - a^2)/(2bc).
Chapter 4: Complex Numbers and Quadratic Equations
Complex Number Standard Form: z = x + iy (where i^2 = -1).
Modulus & Conjugate: |z| = sqrt(x^2 + y^2), Conjugate (z bar) = x - iy.
Multiplicative Inverse: z^(-1) = (z bar) / |z|^2.
Polar Form: z = r(cos(theta) + i sin(theta)) where r = |z| and theta = argument.
Chapter 5: Linear Inequalities
Rules of Inequalities: Multiplying or dividing both sides by a negative number reverses the inequality sign. Graphing solution regions on the Cartesian plane.
Chapter 6: Permutations and Combinations
Factorial Notation: n! = n x (n-1) x ... x 1.
Permutation Formula (Arrangements): nPr = n! / (n - r)!
Combination Formula (Selections): nCr = n! / (r! x (n - r)!)
Matrix Operations: Addition, Scalar multiplication, Multiplication of matrices (A x B).
Transpose: (A')' = A, (A + B)' = A' + B', (AB)' = B'A'.
Symmetric & Skew-Symmetric: A' = A (Symmetric), A' = -A (Skew-Symmetric). Every square matrix can be expressed as sum of a symmetric and skew-symmetric matrix.
Maxima and Minima: First derivative test and Second derivative test (f''(x) < 0 for local maxima, f''(x) > 0 for local minima).
Chapter 7: Integrals
Standard Integrals:
integral x^n dx = x^(n+1)/(n+1) + C,
integral e^x dx = e^x + C,
integral (1/x) dx = log|x| + C,
integral sin(x) dx = -cos(x) + C.
Integration by Parts: integral u v dx = u x integral v dx - integral [ (du/dx) x integral v dx ] dx.
Partial Fractions: Decomposing complex rational expressions into simpler fractions for integration.
Definite Integrals: Fundamental Theorem of Calculus: integral from a to b of f(x)dx = F(b) - F(a). Properties include integral from a to b of f(x)dx = integral from a to b of f(a+b-x)dx.
Chapter 8: Application of Integrals
Area under a Curve: Area = integral from a to b of y dx = integral from a to b of f(x) dx.
Area between Two Curves: Area = integral from a to b of [f(x) - g(x)] dx.
Chapter 9: Differential Equations
Order & Degree: Order is the highest derivative present; Degree is the power of the highest-order derivative.
Variable Separable Method: Rewriting equation as f(x)dx = g(y)dy and integrating both sides.
Linear Differential Equations: dy/dx + Py = Q. Integrating Factor (IF) = e^(integral P dx). Solution: y x IF = integral (Q x IF) dx + C.
Chapter 10: Vector Algebra
Magnitude of Vector: |a| = sqrt(x^2 + y^2 + z^2).
Scalar (Dot) Product: a . b = |a| |b| cos(theta). cos(theta) = (a . b) / (|a| |b|).
Vector (Cross) Product: a x b = |a| |b| sin(theta) n^hat. Area of triangle = 1/2 |a x b|.
Chapter 11: Three Dimensional Geometry
Direction Cosines & Ratios: l, m, n satisfying l^2 + m^2 + n^2 = 1.
Equation of a Line: Vector form: r = a + lambda b. Cartesian form: (x - x1)/a = (y - y1)/b = (z - z1)/c.
Shortest Distance between Two Skew Lines: Formula involving vector cross products and vector differences.
Equation of a Plane: Normal form (r . n = d), Cartesian form (Ax + By + Cz = D).
Chapter 12: Linear Programming
Objective Function: Linear function Z = ax + by to be maximized or minimized subject to constraints expressed as linear inequalities. Corner point method for optimization.
Chapter 13: Probability
Conditional Probability: P(A | B) = P(A intersection B) / P(B).
Multiplication Theorem: P(A intersection B) = P(A) x P(B | A).
Bayes' Theorem: P(E_i | A) = [P(E_i) x P(A | E_i)] / sum[P(E_j) x P(A | E_j)].
Probability Distribution: Mean (Expectation) mu = sum(x_i x P(x_i)), Variance sigma^2 = sum(x_i^2 x P(x_i)) - mu^2.