Can someone explain this model answer i dont get where the root 34 came from ,the centre is -4,2
#Circles
quasi rivet
stoic galleon
The general formula of a circle is x^2 + y^2 = r^2
The r^2 in this case is 34
So to get the radius by itself you square root 34
crimson ocean
The general formula of a circle is x^2 + y^2 = r^2
not really in alevel genreal formula is (x-a)^2 + (x-b)^2 = r^2 as center is not always (0,0)
bold plaza
in the form(x-a)^2 + (y-b)^2=r2
crimson ocean
now frist your going try to put in that form
bold plaza
so just square root to get the actual radius which gives u root 34
crimson ocean
yeah
also the center comes from the form ie (x-a)^2 + (x-b)^2 = r^2 the center is (a,b) so for that equation the center is (-4,2)
bold plaza
i reallly like how simply u solved it
its visually nice. keep an eye out incase i need help with a question pls
crimson ocean
yeah i think this method is most effecient as other method is to work out distances from radius to point on circle (1,5) using distances formula
and you get sqr 34 but thats too long as why not just sub in
bold plaza
exactly thats what i first did and it was just bothersome really
crimson ocean
every circles question has part a ,b and it comes up every AS papers i dont thinkthis topic comes in real alevels that much tho
bold plaza
really?ill keep that in mind
crimson ocean
yeah only 8 questions in every real,mock,speciman from start new spec to 2023
most important topic that come up from y1 is logs but you need know neally all chapters as they get built up in y13 and get harder
bold plaza
would u say coordinate geometry is a big one in mock?