Q8 呢類題目基本上佢年年都出,個重點係搵曬兩條線嘅slope, x-intercept同y-intercept in terms of a,b,c 再進行大細比較,要remind嘅係有時個inequality個分母有unknown就要知道埋個unknown係正定負,先決定到個符號使唔使調轉 Q14 要maximize個area,其實只要maximize所有邊長就得,相反,minimize都係一樣道理(不過注意,有D題目唔會咁simple,有時你maximize 某D邊長,反而會整細個area) Q27 注意apply formula要make sure x^2同y^2 個coefficient係1,所以喺計之前要將C1全式除2,然後再用formula計個centre同radius I. 揾完C1 centre再代落C2條式,睇下係咪0 ll. 揾完radius就會知道 lll. 呢度有兩個methods method 1:兩項兩unknown,solve △(慢嘅方法) method 2: 揾distance between two centre,再揾R1+R2同R1-R2個magnitude,如果IR1-R2I
@punchingkwan30523 жыл бұрын
actually for q27 your method really slow lor, given that statement 1 is correct, and C1 and C2 is not a point circle statement 3 must be correct, just imagine it in your mind the locus drawn must cut C2 in two different point
@ic75713 жыл бұрын
@@punchingkwan3052 當C2係一個fixed circle, 然後 centre of C1 lies on C2,其實喺唔知radius嘅情況下,C1 係可以係一個好大嘅circle,令到佢地冇交點,如果要cut two distinct point,個condition 就要fulfill到0
前提係自己答咗嗰啲確定係啱嘅答案 同埋phy paper 1A好似都係平均分佈 嗰時操卷特登數咗幾年都係8,8,8,9 不過唔肯定有冇記錯 各位考生加油努力溫書頂硬上!
@a.antoniaw3 жыл бұрын
想Pin咗你去 :P
@ChloeCharm-pj5fs Жыл бұрын
我想睇你哋做chem嗰份
@fwd203 Жыл бұрын
Q27 C1: x^2+y^2+2x+4y-149/2=0 C2: x^2+y^2-8x-20y-53=0 For any circle x^2+y^2+Dx+Ey+F=0 Centre (-D/2,-E/2) Radius sqrt((D/2)^2+(E/2)^2-F) Therefore centre of C1 =(-1,-2) Put centre into C2 LHS=RHS I is correct Radius of C1 not equal to radius of C2 (use formula above) II incorrect For III Solve C1 and C2 x^2+y^2+2x+4y-149/2=0 … (i) x^2+y^2-8x-20y-53=0 …(ii) (i) - (ii) 10x +24y = 43/2 Express x in terms of y and substitute into either (i) or (ii) Discriminant of quadratic >0 therefore two distinct intersections