See how one quantity changes another

Represent and interpret relations, functions, straight lines and non-linear graphs.

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Learn the idea

Three things to notice

For each allowed input, a function produces exactly one output.

For two points, gradient = change in y divided by change in x.

m is the gradient and c is the y-intercept, where the line crosses the vertical axis.

Do not memorise the words alone. The worked example shows how to choose and apply the idea.

Syllabus coverage

Relations and functionsFunction notationGradient and interceptStraight-line graphsInverse functionsQuadratic and other graphs