题目内容
(1)化简(
-
)÷(
-
);
(2)计算
lg25+lg2-lg
-log29×log32;
(3)
=i,验算i是否方程2x4+3x3-3x2+3x-5=0的解;
(4)求证:
+
=
.
a |
a+b |
a2 |
a2+2ab+b2 |
a |
a+b |
a2 |
a2-b2 |
(2)计算
1 |
2 |
0.1 |
(3)
-1 |
(4)求证:
sin(
| ||
sin(
|
cos(
| ||
cos(
|
2 |
cos2θ |
(1)原式=
=
.
(2)
lg25+lg2-lg
-log29×log32=lg5+lg2+
-2log23×log32=-
(3)令x=i,左边=2-3i+3+3i-5=0,所以i是所给方程的一个解.
(4)证:左边=
=
=
=
=右边.
| ||||
|
b-a |
a+b |
(2)
1 |
2 |
0.1 |
1 |
2 |
1 |
2 |
(3)令x=i,左边=2-3i+3+3i-5=0,所以i是所给方程的一个解.
(4)证:左边=
sin(
| ||||||||
sin(
|
=
sin
| ||||
sin(
|
=
1 | ||
|
=
2 |
cos2θ |
=右边.
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