107bv3s1sim1
Using Geogebra
geogebra classic
https://www.geogebra.org/classic
8. (a,2) 落在(1,3),(2,5)的直線上, a=?
A=(1,3)
B=(2,5)
f:Line(A,B)
g:y=2
Inetersect(f,g)
9.f(x)=-2x+1 不通過?象限
f(x)=-2x+1
10.L1:4x+(m-1)y=15, L2:(2m+3)x+6y=7, L1垂直L2, m=?
L: ax+by+c=0
斜率 m=-a/b
CAS mode
(using Geogebra Classic)
m1:-4/(m-1)
m2:-(2m+3)/6
Solve(m1 m2=-1,m)
m1:-4/(m-1);m2:-(2m+3)/6;Solve(m1 m2=-1,m)
11. A(1,1),B(3,k) 兩點的斜率為3,k=?
CAS mode
Solve((k-1)/(3-1)=3,k)
15. 三角形三頂點A(0,6),B(-12,-24),C(24,12), 求重心G=?
重心:三中線的交點 =(A+B+C)/3=幾何中心
外心:三中垂線交點=外接圓圓心=到三頂點等距離
內心:三內角平分線交點=內接圓圓心=到三邊等距離
CAS mode
A:(0,6)
B:(-12,-24)
C:(24,12)
(A+B+C)/3
繪圖 mode #multiply commands
Execute({"A:(0,6)","B:(-12,-24)","C:(24,12)","Polygon(A,B,C)"})
Execute({"t1:Midpoint(A,B)","t2:Midpoint(B,C)","t3:Midpoint(A,C)",
"Segment(t1,C)","Segment(t2,A)","Segment(t3,B)"})
16.|3x-5|<9 整數解有幾個?
Geogebra multiple comands
https://wiki.geogebra.org/en/Execute_Command
