Latest posts
Published articles
Filter by board, class, and subject to find notes for exactly what you're studying.
MathematicsClass 12ICSE
How to Find the Largest Box You Can Fold From a Square Sheet
Identify critical, stationary and extreme points, classify local maxima and minima with the first and second derivative tests, and solve optimisation problems by finding absolute maxima and minima on a closed interval.
Read articleMathematicsClass 12ICSE
How the Sign of a Derivative Tells You Whether a Graph Is Climbing
Use the sign of the first derivative to find where a function increases or decreases, prove that a function is increasing or decreasing on an interval, and solve applied problems on intervals of increase and decrease.
Read articleMathematicsClass 12ICSE
How a Single Derivative Gives Both the Tangent and the Normal to a Curve
Find equations of tangents and normals, calculate the angle between two curves where they meet, solve related-rates problems, and apply derivatives to rates of change of geometric and physical quantities.
Read articleMathematicsClass 12ICSE
How Logarithms Tame a Function Like x to the Power x
Use logarithmic differentiation for functions with variable powers and long products, find second-order derivatives of explicit and parametric functions, and choose the right differentiation technique for any function.
Read articleMathematicsClass 12ICSE
How to Differentiate a Curve You Cannot Solve for y
Differentiate composite functions with the chain rule, find derivatives of implicit functions and of curves given in parametric form, and differentiate one function with respect to another.
Read articleMathematicsClass 12ICSE
Why a Sharp Corner Stops a Function From Having a Derivative
Examine the continuity and differentiability of the modulus and greatest integer functions, derive the derivatives of exponential, logarithmic and inverse trigonometric functions, and relate continuity to differentiability.
Read articleMathematicsClass 12ICSE
Why a Function Can Have a Hole You Can Patch With One Point
Test a function for continuity at a point and over an interval, use the algebra of continuous functions for sums, products and quotients, and recognise removable, jump and other discontinuities.
Read articleMathematicsClass 12ICSE
How One Matrix Equation Solves Three Equations at Once
Decide whether a system of linear equations is consistent and how many solutions it has, solve systems with a unique solution using the inverse of the coefficient matrix, and verify the solution.
Read articleMathematicsClass 12ICSE
How a Determinant Finds the Area of a Triangle in One Line
Find the area of a triangle and test collinearity with determinants, form the adjoint of a square matrix and use its properties, and compute the inverse of a 2x2 or 3x3 matrix by the adjoint method.
Read articleMathematicsClass 12ICSE
How to Evaluate a Determinant Without Expanding It
Evaluate determinants of order 2 and 3, find minors and cofactors, use the properties of determinants to avoid full expansion, and solve problems such as factorising determinants with algebraic entries.
Read articleMathematicsClass 12ICSE
Why AB and BA Are Usually Different Matrices
Multiply matrices after checking their orders and see why the product is not commutative, find non-zero matrices whose product is zero, and tell singular from non-singular matrices while proving that an inverse is unique.
Read articleMathematicsClass 12ICSE
Why Every Square Matrix Splits Into a Symmetric and a Skew-Symmetric Part
Classify matrices by type and order, prove and use the properties of symmetric and skew-symmetric matrices, add, subtract and multiply matrices by scalars, and verify the properties of the transpose.
Read articleMathematicsClass 12ICSE
Why the Inverse Tangents of 1, 2 and 3 Add Up to Exactly Pi
Prove and use the co-function identities such as inverse sine plus inverse cosine equals pi by two, the inverse tangent addition and subtraction formulae, the double and triple angle forms, and solve equations with inverse functions.
Read articleMathematicsClass 12ICSE
Why the Inverse of Sine Only Works on a Chosen Range
Define the six inverse trigonometric functions with their domains, ranges and principal branches, sketch their graphs, evaluate principal values, and convert one inverse trigonometric function into another.
Read articleMathematicsClass 12ICSE
Why Only a One-One and Onto Function Can Be Reversed
Classify functions as one-one, many-one, into or onto, find when a function is invertible, form composite functions and inverses, and sketch a function with its inverse as reflections in the line y = x.
Read articleMathematicsClass 12ICSE
Why 'Is Taller Than' Fails a Test That 'Is Equal To' Passes
Define relations on a set and recognise the empty, universal and identity relations, test a relation for the reflexive, symmetric and transitive properties, and decide when it is an equivalence relation.
Read articleMathematicsClass 11ICSE
Why the Chance of Rain or Wind Is Not Just the Two Chances Added
Define probability through the axioms on sets, find the probabilities of 'not', 'and' and 'or' events with set operations, and use the addition theorem for two and three events.
Read articleMathematicsClass 11ICSE
Why Two Batters With the Same Average Can Be Completely Different
Find the range of ungrouped and grouped data, calculate the mean deviation about the mean for both kinds of data, and use measures of dispersion to compare how variable two data sets are.
Read articleMathematicsClass 11ICSE
How Calculus Measures Speed at a Single Instant
See the derivative as an instantaneous rate of change and the slope of a tangent, differentiate simple functions from first principles, use the sum, product and quotient rules, and apply the standard derivative formulae.
Read articleMathematicsClass 11ICSE
What Happens to a Fraction When Its Top and Bottom Both Head to Zero
Understand limits through left-hand and right-hand limits, evaluate standard algebraic, trigonometric, exponential and logarithmic limits, resolve indeterminate forms, and combine limits with the fundamental theorems.
Read articleMathematicsClass 11ICSE
How Three Numbers Pin Down Any Point in a Room
Identify the coordinate axes, planes and octants in three dimensions and plot points, derive and use the distance formula in space, and apply the section and midpoint formulae to points dividing a segment.
Read articleMathematicsClass 11ICSE
How a Fixed Difference of Distances Creates a Curve With Two Branches
Use the standard equation of a hyperbola and the relation between its semi-axes and eccentricity, read its transverse and conjugate axes, vertices, foci, latus rectum and directrices, and apply the focal property.
Read articleMathematicsClass 11ICSE
Why Every Point on an Ellipse Has the Same Total Distance to Two Pins
Use the standard equation of an ellipse and the relation between its semi-axes and eccentricity, read its vertices, foci, latus rectum and directrices, build equations from given data, and apply the focal property.
Read articleMathematicsClass 11ICSE
How the Focus and Directrix Shape Every Parabola
See conics as sections of a double cone with a focus, directrix and eccentricity, derive and sketch the four standard parabolas, read their focus, vertex, directrix, axis and latus rectum, and build equations from a focus and directrix.
Read article