(¸£½¨×¨ÓÃ)2018Äê¸ß¿¼Êýѧ×ܸ´Ï° µÚËÄÕ Èý½Çº¯Êý_½âÈý½ÇÐÎ ¿Îʱ¹æ·¶Á·23 ½âÈý½ÇÐÎ Àí ÐÂÈ˽ÌA°æ ÏÂÔر¾ÎÄ

ËùÒÔAC=8=6.¹ÊÑ¡D.

13.150 ÔÚRt¡÷ABCÖÐ,¡ÏCAB=45¡ã,BC=100 m,ËùÒÔAC=100 m.

ÔÚ¡÷AMCÖÐ,¡ÏMAC=75¡ã,¡ÏMCA=60¡ã,´Ó¶ø¡ÏAMC=45¡ã,ÓÉÕýÏÒ¶¨Àí,µÃ´ËAM=100

m.

m,¡ÏMAN=60¡ã,ÓÉ

,Òò

ÔÚRt¡÷MNAÖÐ,AM=100µÃMN=100

=sin 60¡ã,

=150(m).

=2R=

,

14.½â (1)ÓÉÕýÏÒ¶¨Àí¿ÉµÃ

=2R=(2)ÓÉÕýÏÒ¶¨Àí¿ÉµÃ, ¡àc=2.

22222

ÓÉÓàÏÒ¶¨Àí¿ÉµÃ2=a+b-2abcos 60¡ã,»¯Îªa+b-ab=4. ÓÖa+b=ab,

¡à(a+b)2-3ab=a2b2-3ab=4,½âµÃab=4.

¡à¡÷ABCµÄÃæ»ýS=15.C

absin C=4¡Ásin 60¡ã=

Èçͼ,È¡BCµÄÖеãD,Á¬½ÓPD,ÔòPD=4.ÉèBD=x,ÔòPB=PC=µÃ,(2x)=(2,C2

ÓÉÓàÏÒ¶¨Àí¿É

)+()-2(

2

)cos¡ÏBPC,½âµÃx=3(¸ºÖµÉáÈ¥).ÔòB-,-2

,-2,¹ÊBP,CPµÄÖе㶼ÊÇf(x)ͼÏóµÄ¶Ô³ÆÖÐÐÄ.

sin ¦Øx-2sin

2

16.½â (1)f(x)=+m=sin ¦Øx-1+cos ¦Øx+m

=2sin

ÒÀÌâÒâ

-1+m. =3¦Ð,¦Ø=,

ËùÒÔf(x)=2sin

µ±x¡Ê[0,¦Ð]ʱ,

ËùÒÔf(x)µÄ×îСֵΪm. ÒÀÌâÒâ,m=0. ËùÒÔf(x)=2sin(2)ÒòΪf(C)=2sin¶ø

,

-1+m.

sin

1,

-1.

-1=1,ËùÒÔsin

=1.

ËùÒÔ½âµÃC=

2

ÔÚRt¡÷ABCÖÐ,ÒòΪA+B=,2sinB=cos B+cos(A-C),

2

ËùÒÔ2cosA-sin A-sin A=0, ½âµÃsin A=ÒòΪ0