Jeremy Sim's answer to Rachel's Junior College 1 H2 Maths Singapore question.

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Jeremy Sim
Jeremy Sim's answer
12 answers (Tutor Details)
1st
Oh hey, it's the continuation of the question from last week.

Your lecture notes on composite functions should have a page with 3 circles. Those 3 circles are key to understanding composite functions.

To summarise, gf means putting f inside g. We have discovered that range of f was (1,5] last week. So even if g could take values from any value that is 0 or more, there would never be a time where g will take in an input like 7 or 12, since once I go through the function f I will only get values between 1 and 5.

So to find the range of gf, I will need to know what are the set of values g will take due to f and adjust the range accordingly.