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# sine and cosine rule watch

1. how do you know when to use the sine or cosine rule
2. (Original post by safaa.patel)
how do you know when to use the sine or cosine rule
Depends on what information you have already and what you're looking for, and most importantly, practice.
3. (Original post by safaa.patel)
how do you know when to use the sine or cosine rule
4. tbh you can always start out with the Sine Rule... if it doesn't work switch to the Cosine Rule.
5. (Original post by fatima1998)
thanks
6. (Original post by the bear)
tbh you can always start out with the Sine Rule... if it doesn't work switch to the Cosine Rule.
But it can be time-consuming in exams
7. (Original post by fatima1998)
But it can be time-consuming in exams

you are female... you can multi-task innit

8. The cosine rule is if you have 2 sides and the angle between them, and you're looking for the opposite side (or some rearranged version of that formula).

The sine rule is when you're looking at 2 or 3 sides and the angles opposite them. If more than one angle is known, I'd probably think of the sine rule first, it depends on what you already know.
9. (Original post by the bear)
you are female... you can multi-task innit

in exams i can't even do a whole paper on time

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