#need help circles

80 messages · Page 1 of 1 (latest)

neon solar
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crosses x when y=0

gentle monolith
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have you drew a diagram

neon solar
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using 6b put y=0 and solve

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then yk what D and E are

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icl y i need a diagram for this

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U

gentle monolith
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it ain't gotta be good

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just gotta be a circle in approximately the right area

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much easier to use actual axis

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if D and E cross the x axis then y = 0 yes

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so do that

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yeah u legit know what to do

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brilliant

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who would've thought

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now we need to find the area of DEC

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so we need the base and the height

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yes because those correspond to D and E

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just get rid of the ms tbh

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i can explain it without it

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so we need the area of the triangle

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how do you find the area of a triangle

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so what's the base and what's the height

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the height is not sqrt 18

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what's the centre coordinates

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soooo

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if you are 1 down on the y

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and you need to get to 0 on the y

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what's the height

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yep

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yep

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it's a triangle

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so how could you find the base needed

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solutions of the quadratic

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you literally

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put it in your calculator

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it will give you 4+/- sqrt17

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to solve the quadratic?

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how did you do it then

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how did you solve x²-8x-1=0

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because you're saying you didn't use a calculator

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then how did you get 4+root17

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and 4-root17

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ohh that way

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yes

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this is something you gotta just adapt to

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at a level, you are allowed to solve quadratics and simultaneous equations instantly with your calculator

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this is a general rule unless the question specifically states otherwise

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solving the quadratic...

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the very first part

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you set y = 0

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you get a quadratic in terms of x

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you solve that quadratic to find D and E

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that's why they've made you do (b)

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they specifically set it up that way

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then, just popping that into your calculator will get the roots

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yep

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because we don't need the whole length

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we need the length DM

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where M is the midpoint, hence why they made you do part (a)

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it all ties together, good q tbf

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DE = 2DM

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E is on the x axis, it is not just a random point on the circle

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so what is DM

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look at the x values

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M is 4 across on the x

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and D is -4+root17

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so DM is just root17

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=> DE = 2root17

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yep

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E is 4+root17

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4+root17 ≈ 8.1
-4+root17 ≈ 0.1

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so D is definitely -4+root17

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yep

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yes

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it is a hard question don't worry

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that is not easy for any AS student

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what paper is this from btw? @amber forge

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cool I'll do it tmr see what I get

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im sure you will just remember to sketch stuff if you're confused and don't spend too much time on one question, don't let it get to you, refresh and go to the next q

gentle monolith
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Yes