[DSE 2020] 同學仔開始溫你嘅 數學 未？ [2]

17年個條應該唔洗用都會做到掛都係一part一part咁guide住

其實係
btw 呢份係咪學X社嘅mock

巴打想g依家操ppA1 2之外 仲使唔使做啲額外野

其實都冇 不斷操 起碼兩三次
做齊dse (sp, pp, 12-19)
可以做埋ce (最近10年到, e.g. 00-11)
有時間就埋坊間啦
初中topic我覺得坊間嗰啲ok

*做埋坊間

係呀
計時做個陣 呢part諗左四個字都唔識

學X社啲mock離地開

還可以啦 不過你講完 我先發現到佢每一年既19題都係抄返上一年dse出既topic當練下手都唔錯既
始終dse玩左都就黎十年 可見既將來難度都只會越黎越深

轉下topic先

又係concyclic
btw 下下靠textbook真係會死人

咩叫equation(s) of the graph

應該係equation of locus之類嘅意思

等睇答案

(a)
The graph drawn is a circle
passing through A, B, C

(b)
Let P be the centre
ACB is the angle at circumference
APB is the angle at centre
APB = 2ACB = 60°
As AP = BP (radii), APB is equil.
Let P = (m,n)
Set two eqs using distance formula
Solving, (m,n) = (0,4) or (sqrt3, 1)
As radius = 2, required equations are
x^2 + (y-4)^2 = 4
or (x-sqrt3)^2 + (y-1)^2 = 4

改少少

(a) major arc AB of the circle
passing through A, B, C

(b) 最尾嗰兩條equation個domain
剔番走個minor arc

唉屌
我有數想問都唔好意思問啦
你班老屎忽玩得咁開心

上個post半年先推爆
今個post又會咁撚快嘅

問啦

(out C /DSE 雞唔洗睇)

條equation可能需要加返個restriction
因為唔係一整個圓形

所以我先話等答案

同意 我上面改咗係major arc唔係circle
條equation用半圓再限個domain