GCSE Maths SB AQA H2 End pages:Layout 4
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GLOSSARY
direct proportion Two values or measurements may vary in direct proportion. That is, if one increases, then so does the other.
expand Make bigger. Expanding brackets means you must multiply the terms inside a bracket by the number or letters outside. This will take more room to write, so you have ‘expanded’ the expression.
direct variation Another name for direct proportion. direction The way something is facing or pointing. Direction can be described using the compass points (north, south, south-east, etc.) or using bearings (the clockwise angle turned from facing north). The direction of a vector is given by the angle it makes with a line of reference. Two vectors that differ only in magnitude will be parallel. discriminant The quantity (b2 – 4ac) in the quadratic formula is called the discriminant. distance The separation (usually along a straight line) of two points. do the same to both sides To keep an equation balanced, you must do the same thing to both sides. If you add something to one side, you must add the same thing to the other side. If you double one side, you must double the other side, etc. If you are manipulating a fraction, you must do the same thing to the numerator and the denominator to keep the value of the fraction unchanged. However you can only multiply or divide the numbers. Adding or subtracting will alter the value of the fraction. See also equation. eliminate To remove a quantity such as a variable from an equation. enlargement A transformation of a plane figure or solid object that increases the size of the figure or object by a scale factor but leaves it the same shape, that is, the figure or object remains in the same ratio. (See also scale factor.) equation A number sentence where one side is equal to the other. An equation always contains an equals sign (=). equidistant The same distance apart. equilateral triangle A triangle with three equal sides (and three equal angles – each of which is 60°). 428
expand and simplify An expression involving brackets can be expanded (remove the brackets) and the resulting terms may contain like terms that can then be simplified. exponential function Non-linear equations that have the form y = k x, where k is a positive number. expression Collection of symbols representing a number. These can include numbers, variables (x, y, etc.), operations (+, ×, etc.), functions (squaring, cosine, etc.), but there will be no equals sign (=). exterior angle The exterior angles of a polygon are outside the shape. They are formed when a side is produced (extended). An exterior angle and its adjacent interior angle add up to 180°. factor A whole number that divides exactly into a given number. For example, factors of 30 are 1, 2, 3, 5, 6, 10, 15 and 30. Or, a number or term that divides exactly into an algebraic expression. factorisation (noun) Finding one or more factors of a given number or expression. (verb: factorise) formula (plural: formulae) An equation that enables you to convert or find a measurement from another known measurement or measurements. For example, the conversion formula from the Fahrenheit scale of temperature to the more common Celsius scale is F – 32 C where C is the temperature on the Celsius 5 = 9 scale and F is the temperature on the Fahrenheit scale. frustum The base of a cone or pyramid. The shape obtained by removing the top of a cone or pyramid. function A function of x is any algebraic expression in which x is the only variable. This is often represented by the function notation f(x) or ‘function of x’.