2024 cssa Q32 HELP PLEASEEE (3 Viewers)

yourbestfriend

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Hey, can someone please help me figure out part b of Question 32 before my exam tmrw! I found out part a using the discriminant, but am so lost for part b
thank you!
 

coolcat6778

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C2H6O

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Hey, can someone please help me figure out part b of Question 32 before my exam tmrw! I found out part a using the discriminant, but am so lost for part b
thank you!
ok first step is to break this down visually. we have a circle centered at (1, 3) with radius 3, and a diagonal line at 45 degrees that cuts the circle in two, such that the chord is of length 2root3
1754802677922.png
there are 2 possible values for d

adding in additional info, we can add to the diagram:
1754802924758.png
(i probably shouldnt have made A and B sitting on perfect coordinates but oh well)

using pythag you know the line PQ has to be of length root6, and perfectly diagonal.
im going to try find the green line so d1
all i need is the coordinates for Q, which working from the fact that PQ is diagonal and length root 6, using pythag, Q = (1+root3, 3-root3)
1754803330269.png
equation for line can be found using point gradient form, given that the gradient is 1, to be

rearrange and you get

and

there's probably cleaner solutions but its just a habit of mine to work geometrically to avoid algebraic clutter
also someone lmk if im wrong

edit: just realised this solution probably doesnt satisfy the criteria of find the coordinates of a and b. will come back to this later today if i get the chance, but if anyone else can do it quicker please help
 
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