Concavity of a Function What is concavity? Concavity is the way in which a curve (or surface) bends Mathematically,CONCAVE DOWN is often called concave CONCAVE UP is often called convex Exam...
Manipulating Surds What are surds? If n is a positive integer and is not a square number, then √n (or any multiple of √n ) is a surd Surds are examples of irrational numbers What do I need t...
Laws of Indices What do I need to know about laws of indices? Laws of indices (or index laws – 'index' is the singular, 'indices' is the plural) allow you to simplify and manipulate expressi...
Proof by Contradiction What is proof by contradiction? A proof by contradiction assumes the opposite result is true Then, through a series of logical steps, shows that this cannot be so How ...
Stationary Points & Turning Points What is the difference between a stationary point and a turning point? A stationary point is a point at which the gradient function is equal to zero The tange...
Second Order Derivatives What is the second order derivative of a function? If you differentiate the derivative of a function (i.e. differentiate the function a second time) you get the second orde...
Chain Rule What is the chain rule? How do I know when to use the chain rule? How do I use the chain rule? Are there any standard results for using chain rule? Exam Tip You should aim to be able to ...
Edexcel IGCSE Physics 复习笔记 2.1.3 Resistance Calculating Current, Resistance & Potential Difference Resistance is defined as the opposition to current: The higher the resistance of a ...
Edexcel IGCSE Physics 复习笔记 2.1.2 Voltage & Energy Voltage The terminals of a cell make one end of the circuit positive and the other negative This sets up a potential difference acro...
