鐑偣涓撻」缁?/p>
(
涓�
)
鏁颁笌寮忕殑杩愮畻
绫诲瀷涓�
瀹炴暟鐨勮繍绠?/p>
1
.
(2018路娴峰崡
)
璁＄畻
:3
2
-
-|-
2
|脳
2
-
1
.
瑙ｅ師寮?/p>
=
9
-
3
-
2
脳
=
9
-
3
-
1
=
5
.
2
.
(2018路璐靛窞姣曡妭
)
璁＄畻
:
+
3tan 30掳
-
(蟺
-
)
0
+|
1
-
|.
瑙ｅ師寮?/p>
=-
3
-
2
+
3
脳
-
1
+
-
1
=-
3
-
2
-
1
+
-
1
=-
5
.
绫诲瀷浜?/p>
鏁村紡鐨勮繍绠?/p>
3
.
(2018路鍚夋灄
)
鏌愬悓瀛﹀寲绠�
a
(
a+
2
b
)
-
(
a+b
)(
a-b
)
鍑虹幇浜嗛敊璇?/p>
,
瑙ｇ瓟杩囩▼濡備笅
:
鍘熷紡
=a
2
+
2
ab-
(
a
2
-b
2
)(
绗竴姝?/p>
)
=a
2
+
2
ab-a
2
-b
2
(
绗簩姝?/p>
)
=
2
ab-b
2
(
绗笁姝?/p>
)
(1)
璇ュ悓瀛﹁В绛旇繃绋嬩粠绗?/p>
姝ュ紑濮嬪嚭閿?/p>
,
閿欒鍘熷洜鏄?/p>
;
(2)
鍐欏嚭姝ら姝ｇ‘鐨勮В绛旇繃绋?/p>
.
瑙?/p>
(1)
浜?/p>
鍘绘嫭鍙锋椂娌℃湁鍙樺彿
(2)
鍘熷紡
=a
2
+
2
ab-
(
a
2
-b
2
)
=a
2
+
2
ab-a
2
+b
2
=
2
ab+b
2
.
4
.
(2018路璐靛窞璐甸槼
)
濡傚浘
,
灏嗚竟闀夸负
m
鐨勬鏂瑰舰绾告澘娌胯櫄绾垮壀鎴愪袱涓皬姝ｆ柟褰㈠拰涓や釜鐭╁舰
,
鎷挎帀杈归暱
涓?/p>
n
鐨勫皬姝ｆ柟褰㈢焊鏉垮悗
,
灏嗗墿涓嬬殑涓夊潡鎷兼垚鏂扮殑鐭╁舰
.
(1)
鐢ㄥ惈
m
鎴?/p>
n
鐨勪唬鏁板紡琛ㄧず鎷兼垚鐭╁舰鐨勫懆闀?/p>
;
(2)
m=
7,
n=
4,
姹傛嫾鎴愮煩褰㈢殑闈㈢Н
.
瑙?/p>
(1)
鎷兼垚鏂扮煩褰㈤暱涓?/p>
m+n
,
瀹戒负
m-n
,
鍏跺懆闀夸负
:2[(
m+n
)
+
(
m-n
)]
=
2(
m+n+m-n
)
=
2
m
;
(2)
鎷兼垚鐭╁舰鐨勯潰绉负
(
m+n
)(
m-n
)
=m
2
-n
2
.
褰?/p>
m=
7,
n=
4
鏃?/p>
,
鍘熷紡
=
7
2
-
4
2
=
49
-
16
=
33
.