Sometimes in mathematics we like to use letters to represent numbers. The ‘value’ of these letters can change according to certain rules or conditions we are given – hence we can call them variables.

As the tangent is a straight line, the equation of the tangent will be of the form \(y = mx + c\). We can use perpendicular gradients to find the value of \(m\), then use the coordinates of P to find ...

Google's latest doodle in India celebrates the quadratic equation, ax² + bx + c = 0, showcasing its real-world applications ...