Hi there
So I understand this is probably a silly question but when do you use the sine rule and the cosine rule? I understand the maths of it just identifying the situation of which to use is what I'm struggling with. Any tips?
Usually you get used to when to use what with practice. However, some people do prefer the guidelines as to when to use what rule:
Finding an angle- Given two sides and an angle - use sine rule
- Given three sides - use cosine rule
Finding a side length- Given one side and two angles - use sine rule
- Given two sides and one angle - use cosine rule
The guidelines may help at first, but relying on them can be hard because it's easy to mix it up. Which is why with enough practice, people start becoming more reliant on intuition instead.
And there's also the rule of thumb: if one of the two doesn't work, it's most likely the other.