Mathematics – Class 9 – CBSE Syllabus

Review of representation of natural numbers, integers, rational numbers on the number line. Representation of terminating/non-terminating recurring decimals on the number line through successive magnification, Rational numbers as recurring/ terminating decimals. Operations on real numbers.

Examples of non-recurring/nonterminating decimals. Existence of non-rational numbers (irrational numbers) such as \(\sqrt{2}\), \(\sqrt{3}\) and their representation on the number line. Explaining that every real number is represented by a unique point on the number line and conversely, viz. every point on the number line represents a unique real number.

Definition of nth root of a real number.

Rationalization (with precise meaning) of real numbers of the type \(\dfrac{1}{a + b\sqrt{x}}\) and \(\dfrac{1}{\sqrt{x} + \sqrt{y}}\) (and their combinations), where \(x\) and \(y\) are natural numbers and \(a\) and \(b\) are integers.

Recall of laws of exponents with integral powers. Rational exponents with positive real bases (to be done by particular cases, allowing learner to arrive at the general laws.)

Definition of a polynomial in one variable, with examples and counter examples. Coefficients of a polynomial, terms of a polynomial and zero polynomial.

Degree of a polynomial.

Constant, linear, quadratic and cubic polynomials. Monomials, binomials, trinomials. Factors and multiples.

Zeroes of a polynomial.

Motivate and State the Remainder Theorem with examples.

Statement and proof of the Factor Theorem. Factorization of ax² + bx + c, a ≠ 0 where a, b and c are real numbers, and of cubic polynomials using the Factor theorem.

Recall of algebraic expressions and identities. Verification of identities: (x + y + z)² = x² + y² + z² + 2xy + 2yz + 2zx; (x ± y)³ = x³ ± y³ ± 3xy(x ± y); x³ + y³ = (x + y)(x² − xy + y²); x³ − y³ = (x − y)(x² + xy + y²); x³ + y³ + z³ − 3xyz = (x + y + z)(x² + y² + z² − xy − yz − zx); and their use in factorization of polynomials.

Recall of linear equations in one variable.

Introduction to the equation in two variables. Focus on linear equations of the type \(ax + by + c = 0\). Explain that a linear equation in two variables has infinitely many solutions and justify their being written as ordered pairs of real numbers, plotting them and showing that they lie on a line.

The Cartesian plane, coordinates of a point

Names and terms associated with the coordinate plane, notations.

History - Geometry in India and Euclid's geometry. Euclid's method of formalizing observed phenomena into rigorous Mathematics with definitions, common/obvious notions, axioms/postulates and theorems.

The five postulates of Euclid. Equivalent versions of the fifth postulate. Showing the relationship between axiom and theorem, for example: (a) Given two distinct points, there exists one and only one line through them. (Axiom) (b) Two distinct lines cannot have more than one point in common. (Theorem)

(State without proof) If a ray stands on a line, then the sum of the two adjacent angles so formed is 180° and the converse.

(Prove) If two lines intersect, vertically opposite angles are equal.

(State without proof) Lines which are parallel to a given line are parallel.

(State without proof) Two triangles are congruent if any two sides and the included angle of one triangle is equal (respectively) to any two sides and the included angle of the other triangle. (SAS Congruence)

(Prove) Two triangles are congruent if any two angles and the included side of one triangle is equal (respectively) to any two angles and the included side of the other triangle. (ASA Congruence)

(State without proof) Two triangles are congruent if the three sides of one triangle are equal (respectively) to three sides of the other triangle. (SSS Congruence)

(State without proof) Two right triangles are congruent if the hypotenuse and a side of one triangle are equal (respectively) to the hypotenuse and a side of the other triangle. (RHS Congruence)

(Prove) The angles opposite to equal sides of a triangle are equal.

(State without proof) The sides opposite to equal angles of a triangle are equal.

(Prove) The diagonal divides a parallelogram into two congruent triangles.

(State without proof) In a parallelogram opposite sides are equal, and conversely.

(State without proof) In a parallelogram opposite angles are equal, and conversely.

(State without proof) A quadrilateral is a parallelogram if a pair of its opposite sides is parallel and equal.

(State without proof) In a parallelogram, the diagonals bisect each other and conversely.

(State without proof) In a triangle, the line segment joining the midpoints of any two sides is parallel to the third side and is half of it and (State without proof) its converse.

(Prove) Equal chords of a circle subtend equal angles at the center and (State without proof) its converse.

(State without proof) The perpendicular from the center of a circle to a chord bisects the chord and conversely, the line drawn through the center of a circle to bisect a chord is perpendicular to the chord.

(State without proof) Equal chords of a circle (or of congruent circles) are equidistant from the center (or their respective centers) and conversely.

(Prove) The angle subtended by an arc at the center is double the angle subtended by it at any point on the remaining part of the circle.

(State without proof) Angles in the same segment of a circle are equal.

(State without proof) If a line segment joining two points subtends equal angles at two other points lying on the same side of the line containing the segment, the four points lie on a circle.

(State without proof) The sum of either pair of the opposite angles of a cyclic quadrilateral is 180° and its converse.

Area of a triangle using Heron's formula (without proof).

Surface areas and volumes of spheres (including hemispheres) and right circular cones.

Bar graphs.

Histograms (with varying base lengths).

Frequency polygons.