浜烘暀鐗堟暟瀛﹀繀淇簲妯″潡缁煎悎娴嬭瘯棰?/p>
锛?/p>
鏃堕棿
120
鍒嗛挓锛屾弧鍒?/p>
150
鍒?/p>
锛?/p>
涓�銆侀�夋嫨棰?/p>
锛?/p>
鏈ぇ棰樺叡
12
涓皬棰橈紝姣忓皬棰?/p>
5
鍒嗭紝鍏?/p>
60
鍒?/p>
.
鍦ㄦ瘡涓皬棰樼粰鍑虹殑鍥涗釜閫夐」涓紝
鍙湁涓�椤规槸绗﹀悎棰樼洰瑕佹眰鐨?/p>
锛?/p>
1
锛庢暟鍒?/p>
0
锛?/p>
1
锛?/p>
0
锛?/p>
-1
锛?/p>
0
锛?/p>
1
锛?/p>
0
锛?/p>
-1
锛?/p>
鈥?/p>
鐨勪竴涓�氶」鍏紡鏄?/p>
锛?/p>
锛?/p>
A
锛?/p>
飥?/p>
飥?/p>
2
1
1
飥?/p>
飥?/p>
n
B
锛?/p>
cos
2
飦?
n
C
锛?/p>
cos
飥?/p>
飥?/p>
2
1
飦?/p>
飥?/p>
n
D
锛?/p>
cos
飥?/p>
飥?/p>
2
2
飦?/p>
飥?/p>
n
鎬濊矾鍒嗘瀽锛?/p>
鍒嗗埆鍙?/p>
n=1
锛?/p>
2
锛?/p>
3
锛?/p>
4
浠ｅ叆楠岃瘉鍙緱
.
绛旀锛?/p>
B
2
锛庡凡鐭?/p>
鈻?/p>
ABC
鐨勪笁杈归暱鍒嗗埆涓?/p>
a-2
锛?/p>
a
锛?/p>
a+2
锛屼笖瀹冪殑鏈�澶ц鐨勬寮﹀�间负
2
3
锛屽垯杩欎釜涓夎褰?/p>
鐨勯潰绉槸
锛?/p>
锛?/p>
A
锛?
4
15
B
锛?
4
3
15
C
锛?/p>
4
3
2
D
锛?
4
3
35
鎬濊矾鍒嗘瀽锛?/p>
鍏堝垽鏂嚭
a+2
鎵�瀵硅鏈�澶э紝璁句负
伪
锛屽垯
sin
伪
=
2
3
锛屸埓
cos
伪
=
卤
2
1
.
褰?/p>
cos
伪
=
2
1
鏃讹紝鐢?/p>
(a+2)
2
=a
2
+(a-2)
2
-2a(a-2)
路
cos
伪
锛岃В寰?/p>
S=0
锛屼笉鍚堥鎰?/p>
.
褰?/p>
cos
伪
=-
2
1
鏃讹紝鐢?/p>
(a+2)
2
=a
2
+(a-2)
2
-2a(a-2)
路
cos
伪
锛岃В寰?/p>
a=5
鎴?/p>
a=0(
鑸嶅幓
).
鈭?/p>
S=
2
1
(a-2)
路
a
路
sin
伪
=
2
1
脳
3
脳
5
脳
2
3
=
4
3
15
.
绛旀锛?/p>
B
3
锛庡湪绛夋瘮鏁板垪
{a
n
}
涓紝
a
9
+a
10
=a
锛?/p>
a鈮?
锛夛紝
a
19
+a
20
=b
锛屽垯
a
99
+a
100
绛変簬
锛?/p>
锛?/p>
A
锛?/p>
8
9
a
b
B
锛庯紙
a
b
锛?/p>
9
C
锛?/p>
9
10
a
b
D
锛庯紙
a
b
锛?/p>
10
鎬濊矾鍒嗘瀽锛?/p>
鈭?/p>
a
19
+a
20
=a
9
q
10
+a
10
q
10
=q
10
(a
9
+a
10
)(q
涓哄叕姣旓級锛?/p>
鈭?/p>
q
10
=
10
9
20
19
a
a
a
a
飥?/p>
飥?/p>
=
a
b
.
鍙?/p>
a
99
+a
100
=a
19
q
80
+a
20
q
80
=q
80
(a
19
+a
20
)=(
a
b
)
8
路
b=
8
9
a
b
.
绛旀锛?/p>
A
4
锛?/p>
棣栭」涓?/p>
2
锛?/p>
鍏瘮涓?/p>
3
鐨勭瓑姣旀暟鍒楋紝
浠庣
n
椤瑰埌绗?/p>
N
椤圭殑鍜屼负
720
锛?/p>
鍒?/p>
n
銆?/p>
N
鐨勫�煎垎鍒槸
锛?/p>
锛?/p>
A
锛?/p>
n=2
锛?/p>
N=6
B
锛?/p>
n=2
锛?/p>
N=8
C
锛?/p>
n=3
锛?/p>
N=6
D
锛?/p>
n=3
锛?/p>
N>6
鎬濊矾鍒嗘瀽锛?/p>
鈭?/p>
S
N
-S
n-1
=720
锛?/p>
鈭?/p>
3
1
)
3
1
(
2
3
1
)
3
1
(
2
1
飥?/p>
飥?/p>
飥?/p>
飥?/p>
飥?/p>
飥?/p>
n
N
=720
锛屽嵆
3
N
-3
n-1
=720.