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# Polar co ordinates; finding area watch

1. (I guessed 3pi) Does this make sense without the range given?
2. (Original post by ckfeister)

(I guessed 3pi) Does this make sense without the range given?
If no range is given, you can presume that they mean that all values of theta are acceptable, that it, from 0 to 2pi (or -pi to pi, whichever convention you are using). It really helps if you can come up with a basic sketch, as there are often symmetry ideas that can save you a lot of time.
3. (Original post by ckfeister)

(I guessed 3pi) Does this make sense without the range given?
Yes because if you sketch it, it's an enclosed shape on it's natural domain so the area would be bounded by it entirely on
4. (Original post by Pangol)
If no range is given, you can presume that they mean that all values of theta are acceptable, that it, from 0 to 2pi (or -pi to pi, whichever convention you are using). It really helps if you can come up with a basic sketch, as there are often symmetry ideas that can save you a lot of time.
(Original post by RDKGames)
Yes because if you sketch it, it's an enclosed shape on it's natural domain so the area would be bounded by it entirely on
Where did I do a stupid mistake?

5. (Original post by ckfeister)
Where did I do a stupid mistake?

cos (-pi) = -1, same as cos pi not - cos pi

So these two terms cancel out.

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