MAT - Paper 2017 - Q2
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.