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# General questions about c2 exam watch

1. So with the exam coming up, I have a few general questions that I would find helpful if somebody answered.

-What formulas do we have to know for the shapes? Like cuboid volume, sphere volume, cylinder volume?
-How do we know when to use either the sine or the cosine rule? Is there a general rule for it?
2. I've heard they're scraping the formula book
3. (Original post by frostyy)
So with the exam coming up, I have a few general questions that I would find helpful if somebody answered.

-What formulas do we have to know for the shapes? Like cuboid volume, sphere volume, cylinder volume?
-How do we know when to use either the sine or the cosine rule? Is there a general rule for it?
I don't know about the first one - the formula booklet has a few formulae if I remember correctly (you can find it online, I can't link it at the moment).

If you look at what both rules are finding, you'll find that one works better than the other depending on what you have. The sin rule requires at lest one known angle, whereas the cosine rule does not need any angles if you are given 3 lengths and asked to find the angle.
4. (Original post by Brookevesxoxo)
I've heard they're scraping the formula book
Lol.

They tend to give the formulas for any necessary shapes in the questions if not common knowledge.

Cosine rule:
find any angle with 3 lengths
find a length with 2 sides and the angle between.

Sine rule:
Think about having opposite information for this one;
find an angle if you know the length opposite to this angle and another angle/length pair (must be opposite)
find a length if you know two angles and the length opposite to one of the angles.

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Updated: May 23, 2016
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