Teach Genie
Teach it back in your own words, spot gaps, and remember it better.
A function is a rule that gives exactly one output for each input. In f(3)f(3)f(3), the 3 is the input and the value you get after applying the rule is the output.
To evaluate a function, replace every xxx with the given input. Use brackets for negative inputs, so h(−4)=2(−4)2−6h(-4)=2(-4)^2-6h(−4)=2(−4)2−6, not 2−42−62-4^2-62−42−6.
Function notation is the language used for inverse and composite functions too. Once substitution is secure, you can start undoing rules with f−1(x)f^{-1}(x)f−1(x) and chaining rules with g(f(x))g(f(x))g(f(x)).
Question 1
2 marksGiven that f(x)=x−4f(x) = x - 4f(x)=x−4 find:
A function is a rule that takes an input and gives exactly [ ] output.
Revision notes for Edexcel GCSE Maths Inverse and Composite Functions. Open the guide for explanations and worked examples. Written against the Edexcel GCSE Maths (1MA1) specification, so the content matches what's examinable rather than general Maths background.
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Let h(x)=3x2−5h(x)=3x^2-5h(x)=3x2−5. What is h(−2)h(-2)h(−2)?
