More Quadratics!

The last post was about the importance of Quadratic Equations…and the fact they appear everywhere…and at all levels.

On the 2022 LCOL P1 we have a couple of prime examples. In the first slide we need to use the -b formula and in the second we use factorising…

One thing I don’t like about either of these questions is that the examiner is not allowing student to fully show off what they can do.
In the first we solve the quadratic to find a maximum…but the students didn’t do any of the differentiation …and they were told to let the ‘given’ derivative equal 0.

In the second we are using the Sn formula for summing a series but it was partially filled in…and again let equal to 0.



Students didn’t really need any knowledge of differentiation or patterns for these parts…just Algebra (though they would lose a mark for not stating that x=4.54 was the max…)…so a little knowledge needed for full marks.

Hoping to get the solutions to the LCOL 2022 and LCHL 2022 papers out this week. Finalising these…along with the new website so lots of new material on the way.

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