MAT - Paper 2012 - Q1G
Flashcards
Why not to reach for matrices
Why shouldn’t you use matrices to tackle MAT questions like this?
Why shouldn’t you use matrices to tackle MAT questions like this?Because there are no matrices in the exam spec, so the question has been written to be solved differently.
Sign and singular cases of the solution
\[y = \frac{4 - 2k}{k - 2}\]
Why can’t $y$ ever be positive?
For $4 - 2k$ to be positive, $k$ has to be less than $2$. However, when $k$ is less than $2$, $k - 2$ is negative.
You’ve rearranged some simultaneous equations and got
\[y = \frac{4 - 2k}{k - 2}\]
Why is still worth trying to substitute $k = 2$ back into the original equation?
Because $k = 2$ might be a special ‘singular’ case.