23.10
ͼAOB=COD=90㣬
1COB=60㣬ָͼԵOΪĽУΪǵĽDz˵. 2COB=
3?AOD?AODĶ 7
24.10
Ķн̣㣺(?5)?(?)?20
1514⣺ԭʽ=(?5)?(?)?20 һ ?(?5)?(?4) ڶ ??20 1
һǵ ԭ ڶǵ ԭ 2ȷĽд
15 25.10
֪ͬһֱϵPMN 1NPٻֱMP
2MNӳMNRʹNR=MN ͼۼдͼ̣
3?PNRȡPNM100㣬PNRĶ. 26.12
115ף2ӯӯеһ6000ԪףƷƷļȼƷƷĽۺۼ±ע=ۼۣۣ
ۣ/Ԫ ۼۣ/Ԫ 22 29 30 40 1һνʱףƷټ
2óеڶԵһεĽֹףƷмƷļ䣬Ʒļ
һε3ƷԭۣƷۡڶƷӯ2130ԪڶƷǰԭ۴۵ġ
ѧĩʲ
꼶ϣοֱ
ľֻ֤ⷨҪȷɲձ鸳֣
һѡ⣨40֣BDBAA BABDB 110⣩ ⣨32֣
11? 127 13?(3y?5) 142n 1534㣻 16 1710 1812
19ÿС6֣12 ⣺ԭʽ=?1?1511??[2?9]--------------------------------------------------2 23 =?1?1?(?7)-----------------------------------------------------------4 6 =
1--------------------------------------------------------------------------6 62⣺ԭʽ=5a?3b?3a?6b?10a?4b-----------------2 =?2a?5b------------------------------------------4 =?2?(?1)?5?1-------------------------------------5 =?7--------------------------------------------------6 208֣
⣺ȥĸ6x?3(2x?1)?6?2(1?x)--------------------------------------2
ȥţ6x?6x?3?6?2?2x-------------------------------------------4 6x?6x?2x?6?2?3----------------------------------------------6 ϲͬ?2x?1-----------------------------------------------------------7 ϵһx??218֣
22222222221---------------------------------------------------------------8 2⣺
--4
113?1?0??1??2??422
------------------------------------------------------------8
22 8֣
21Ӱ
S=(3)?11xy?xy-----------------------2 22
?9x2?xy------------------------------------4
(2)=8y=2ʱ