Christian Lawson-Perfect

Christian Lawson-Perfect on Equations of straight lines MCQ 8 years, 5 months ago

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Christian Lawson-Perfect on Equations of straight lines MCQ 8 years, 5 months ago

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I fixed a typo, but otherwise this looks good!

Christian Lawson-Perfect on Mathematical formulae - Volume 8 years, 5 months ago

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Christian Lawson-Perfect on Mathematical formulae - Volume 8 years, 5 months ago

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Christian Lawson-Perfect on Surds simplification 8 years, 5 months ago

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Christian Lawson-Perfect on Surds simplification 8 years, 5 months ago

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I'd like a description of how you decide if a root is a surd or not, like "$\sqrt{a}$ is a surd because there is no whole number $b$ such that $b^2 = a$".

Similarly for part b), describe the strategy: find a square number which divides $a$, and rewrite as $\sqrt{b^2} \times \sqrt{c}$. (Or, do what I did and multiply out the $a\sqrt{b}$ forms - much easier!)

Otherwise, this looks good.

Christian Lawson-Perfect on Compute the partial sum of an arithmetic sequence 8 years, 5 months ago

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Christian Lawson-Perfect on Compute the partial sum of an arithmetic sequence 8 years, 5 months ago

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Fixed a few typos...

You need to show the limits of the sum: $\sum_{i=1}^n$ instead of just $\sum$.

There are a couple of steps you need to carry out in order to work out the partial sum given a list of the elements:

• Identify $a_1$ and $a_n$.
• Calculate $n$.

These could be in Steps, to guide students through the calculation.

Similarly in part b), you need to identify the first term and common difference; these could be Steps.

You've put i) and ii) in the advice, but not in the question itself! And they're basically the same question, aren't they?

The advice uses $d$ for the common difference, but never introduces it. And if your first term is $a_0$ instead of $a_1$, the formula for $a_n$ is a lot nicer.

I don't like "We need to find the difference between $20 \rightarrow 30 \rightarrow 40$". That's not a sentence! I'd prefer something like "We need to find $d$, the common difference between consecutive terms in the sequence."

This could be split into two separate questions.

Christian Lawson-Perfect on Limits of accuracy in measuring weight in a gym scenario 8 years, 5 months ago

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Christian Lawson-Perfect on Limits of accuracy in measuring weight in a gym scenario 8 years, 5 months ago

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