如图,C在直线BE上,∠ABC与∠ACE的角平分线交于点A1, (1)若∠A=60°,求∠A1的度数; (2)若∠A=m,求∠A1的度数; (3)在(2)的条件下,若再作∠A1BE、∠A;1CE的平分线,交于点A2;再

问题描述:

如图,C在直线BE上,∠ABC与∠ACE的角平分线交于点A1

(1)若∠A=60°,求∠A1的度数;
(2)若∠A=m,求∠A1的度数;
(3)在(2)的条件下,若再作∠A1BE、∠A;1CE的平分线,交于点A2;再作∠A2BE、∠A2CE的平分线,交于点A3;…;依此类推,则∠A2,∠A3,…,∠An分别为多少度?

∵∠A1=∠A1CE-∠A1BC
=

1
2
∠ACE-
1
2
∠ABC
=
1
2
(∠ACE-∠ABC)
=
1
2
∠A.
∴(1)当∠A=60°时,∠A1=30°;
(2)当∠A=m时,∠A1=
1
2
m;
(3)依此类推∠A2=
1
4
m,∠A3=
1
8
m,∠An=(
1
2
)n
m.