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第 22 週 · 應試銜接 · 第 5 節

P2 多選 45 題戰術 —— 75 分鐘的時間戰爭

卷二 45 題佔總分 35%,平均一題只有 100 秒。這節不教新知識,純教戰術:會的題怎麼快(速解模板)、不會的題怎麼猜得聰明(四大選項戰術)、每年必出的 Section B 題型提前鎖死,最後補上課程沒教過的「數制」漏洞。

▶ 第一關: 四大選項戰術
P2 time war: 75 min / 45 questions75minstartSec A: Q1-3040 min (80 s each)Sec B: Q31-4530 min (2 min each)mark sheet+ check: 5 minaverage 100 s per questionstuck for 2 min? mark it, skip, come back
MC decision flow (per question)read the question (about 15 s)know the method?YESsolve directly(fast lane, 40-80 s)NOeliminate wrong options(units / sign / extreme case)substitute numbers /back-substitute the optionsstill stuck at 2 min?mark it, skip, guess laternext questionnever leave a blank - no penalty for guessing
▶ 第二關: Section A 速解模板
measured 25 m, to the nearest m24.52525.50.50.524.5 ≤ true length < 25.5 (error = half the unit)includedexcluded
▶ 第三關: Section B 必考鎖定
powers of i: a 4-step cyclei−1−i1×i×i×i×ii¹ = ii² = −1i³ = −ii⁴ = 1 (repeat)rule: n ÷ 4, keep remainder2026 = 4×506 + 2so i^2026 = i² = −1
where z puts you on the normal curve-3-2-10123μ = 79 (mean), σ = 8Boy: 55(z = −3)Girl: 95(z = +2)bigger z = further above the mean = relatively better
six moves from mother graph y = f(x) (grey dashed)f(x)+k : UPf(x+k) : LEFT−f(x) : flip x-axisf(−x) : flip y-axisa·f(x) : stretch ×af(bx) : squeeze ×1/binside ( ) = horizontal + opposite / outside = vertical + direct
⚔ BOSS: 補漏(數制·四心)+ 高危題型
AD08 (hex) → denary by place valueAD0816³ = 409616² = 25616¹ = 1616⁰ = 110×409613×2560×168×1= 40960= 3328= 0= 840960 + 3328 + 0 + 8 = 44296A=10 B=11 C=12 D=13 E=14 F=15quick check: last digit 8 is even → answer must be even
the four centres of a triangle21centroid = medians meetcuts each median 2 : 1orthocentre = altitudes meetright tri: at the right angleincentre = bisectors meetequidistant from 3 sidescircumcentre = perp bisectorsequidistant from 3 verticesright triangle: orthocentre = right-angle vertex,circumcentre = midpoint of hypotenuse (R = hyp/2)