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C2/ basic trig HELP Watch

1. Hello,

Another simple question,
In C2 when I have to apply the sine and cosine rule I can always tell for some reason but I don't have an explanation why, but however how do you really know when to apply it? Like properly.
In a non-right angled triangle you use those two rules and in a right angled you use SOH CAH TOA right?

But again my question really remains is when to know which rule to apply (sine and cosine).
2. I think I worked it out, looking at the questions is it when you have two sides with an angle in between you use cosine and if you have two sides but the angle is not in between you use sine?
3. (Original post by QUANTAM)
Hello,

Another simple question,
In C2 when I have to apply the sine and cosine rule I can always tell for some reason but I don't have an explanation why, but however how do you really know when to apply it? Like properly.
In a non-right angled triangle you use those two rules and in a right angled you use SOH CAH TOA right?

But again my question really remains is when to know which rule to apply (sine and cosine).
When you have 2 sides and an angle or 2 angles and 1 side, and want to figure out another opposite angle or side e.g. find angle b or side b, use sin rule a/sin a = b/sin b.

Finding out a non opposite side or angle, use cosine rule, e.g. finding out a when you only have b, c and another angle which is A, or angle A when you only have a,b and angle B.
It's kinda hard to explain... look up some diagrams
4. alright thanks

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