# MAT - Paper 2017 - Q2

> Source: https://ollybritton.com/notes/maths/problems/mat/2017/q2/ · Updated: 2021-10-22 · Tags: mat, notes, maths

## Flashcards
### 2021-10-22
##### What is it sometimes constructive to do with a system of equations where at least one of the entries is always zero??
Add up all the equations rather than just a pair.

##### When equating coefficients, what must you check??
That you're actually equating it to something they've told you must exist.

##### If you've been given that $$\frac{1}{1 + \alpha} = A + B\alpha + C\alpha^2$$ why can't you just do $$1 \equiv (1 + \alpha)(A + B\alpha + C\alpha^2)$$ and compare coefficients??
Because you'd end up with a cubic expression on one side, and they haven't told you that exists.

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