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A-Level Maths C2 - Coordinate Geometry

Hi guys!!

I just have a quick question regarding the equation of circles!

Attachment not found


As you can see above, do I have to simplify (root 5) squared and write is as 5 or can I leave it like that and still get the full marks??

Thank you for your help in advance.
you should write it as a 5
yes you need to simplify because the standard equation of a circle doesn't equal a root.
Reply 3
Thanks you and would I lose marks if I don’t??

Also, in some questions where they ask to find the equation of the line and the question doesn’t specify what form in, would it matter if it’s in ax+by=0 or y=mx+c? If you don’t mind me asking, of course. Thank you
Reply 4
Thank you so much guys!!
Original post by Newshsnik
Thanks you and would I lose marks if I don’t??

Also, in some questions where they ask to find the equation of the line and the question doesn’t specify what form in, would it matter if it’s in ax+by=0 or y=mx+c? If you don’t mind me asking, of course. Thank you


You would lose the a1 accuracy mark.

I use the rule of thumb that if x is negative then I'll move it to the LHS to make it positive. I don't know if this is necessary, it's just how I do it.
Reply 6
Okay thank youu
Original post by Newshsnik
Hi guys!!

I just have a quick question regarding the equation of circles!

As you can see above, do I have to simplify (root 5) squared and write is as 5 or can I leave it like that and still get the full marks??

Thank you for your help in advance.


Either answer would be accepted, but you should aim to write expressions in their simplest form possible.
As for the lines, any form will be accepted as long as it's the correct one.

I'm no examiner, but generally in maths it doesn't matter that much unless a question specifies which form it wants the answer in.
Original post by Newshsnik
Hi guys!!

I just have a quick question regarding the equation of circles!

Attachment not found


As you can see above, do I have to simplify (root 5) squared and write is as 5 or can I leave it like that and still get the full marks??

Thank you for your help in advance.


Simplify as much as you can, but not too much
Reply 9
Thank youu so much.

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