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STEP Support Programme

Pure STEP module Q12iii

Hi,
Bit stuck on how to get the last part of iii). Had a look at the discussion, but I'm not sure where its leading to... I've tried a couple of expressions but none of them have worked

Thanks

Hello! For this part of the question it's good to try to guess the answer, based on the previous result given (maybe it will look similar), then try to show that your guess is right. What expressions have you tried so far?

Well I finished the rest of the questions now, and had a look at the solutions as I was making no progress with iii, but I still don't understand which bit of ii is useful for guessing the answer? I think I may be missing something here, could you tell me the reasoning behind finding the answer as I'm confused.

Thanks a lot

In the result you are asked to "Show" there is one bracket on the LHS and two on the RHS, with 3 letters appearing on the LHS and 4 (one repeated) on the RHS.

The $Z$ appears outside the bracket on the LHS, and then occurs twice on the RHS. Also the letters in the bracket on the LHS stay in the same order on the RHS.

Using these observations you can make a guess at what $X*(Y*Z)$ can be written as.

(I can put in a bit more detail if you need it).

Useful Links

Underground Mathematics: Selected worked STEP questions

STEP Question database

University of Cambridge Mathematics Faculty: What do we look for?

University of Cambridge Mathematics Faculty: Information about STEP

University of Cambridge Admissions Office: Undergraduate course information for Mathematics

Stephen Siklos' "Advanced Problems in Mathematics" book (external link)

MEI: Worked solutions to STEP questions (external link)

OCR: Exam board information about STEP (external link)

AMSP (Advanced Maths Support programme): Support for University Admission Tests (external link)