In a circle, why are the two corners of a chord complementary to each other? Such as the title

In a circle, why are the two corners of a chord complementary to each other? Such as the title

Because the circle angle is equal to half of the center angle of the arc, and the sum of the two center angles of the arc and the chord is 360 degrees, the sum of the two circle angles of the chord is 180 degrees, that is, they are complementary

Decomposition factor: X3 + 9 + 3x2 + 3x

x3+9+3x2+3x=x3+3x2+3x+9=x2（x+3）+3（x+3）=（x+3）（x2+3）．

In the parallelogram ABCD, ab = 12, diagonal AC = 10, BD = 26, find the area of parallelogram ABCD

The area formula of parallelogram can be solved by half of 1 / 2 diagonal
Area = 1 / 2 (10 * 26) = 130

Solve the equation. X △ 12 / 25 = 5 / 14

Original formula = > 25X / 12 = 5 / 14
5x/12=14
5x/6=7
35x=6
x=6/35

There are several common tangents of two circles x ^ 2 + y ^ 2 + 2Y + 2y-2 = 0 x ^ 2 + y ^ 2-4x-2y + 1 = 0

The equations of the two circles are: (x + 1) &# 178; + (y + 1) &# 178; = 4 (X-2) &# 178; + (Y-1) &# 178; = 4, the center of the circle is (- 1, - 1), (2,1), the radius is 2, so the center distance of the two circles is √ 13, so the radius difference ＜ the center distance ＜ the sum of the radius, so the two circles intersect

In rational numbers, integers rather than positive numbers are collectively referred to as (), and negative numbers rather than fractions are collectively referred to as ()

Linzoe day,
In rational numbers, numbers that are integers but not positive numbers are collectively called (non positive integers), and numbers that are negative numbers but not fractions are collectively called (negative integers)

Given the function f (x) = | X & # 178; - 1 | + X & # 178; + KX, and the definition field is (0,2)
(1) If the equation f (x) about X has two different solutions x1, X2 on (0,2), the range of K is obtained
(2) If f (x) is a monotone function over the domain of definition, the value range of K is obtained

When 0

If the reciprocal of (3 / a) and (3 / 2a-9) are opposite to each other, what is the value of a

The reciprocal of (A / 3) = 1 / (A / 3) = 3 / A
And (2a-9 / 3) are opposite to each other
So 3 / a = - (2a-9) / 3
So - 9 = 2A ^ 2-9a
2a^2-9a+9=0
(a-3)(2a-3)=0
a=3,a=3/2

The following equations are continued: 1. X + y = 7, y + Z = 8, x + Z = 9, 2.5x + y + Z = 6, x + 5Y + Z = - 2, x + y + 5Z = 10

1.
（1）x+y=7
（2） y+z=8
（3） x+z=9
(1) The formula is as follows: x = 7-y is substituted into (3) to get (4)
（4）（7-y）+z=9
-Y + Z = 2 plus (2)
y+z=8
2z=10
Substituting z = 5 into (2) yields
Y = 3 is substituted into (1)
x=4
two
（1）5x+y+z=6
（2） x+5y+z=-2
（3） x+y+5z=10
(2) (3) subtract to get (4)
-4Y + 4Z = 12 (at the same time △ 4) to get (4)
（4）-y+z=3
(2) Formula two sides × 5 get (5)
(5) 5x + 25y + 5Z = - 10 minus (1) to get (6)
（1）5x+y+z=6
(6) 24y + 4Z = - 16 (both sides △ 4)
6y + Z = - 4 minus (4)
-y+z=3
7y=-7
Y = - 1 to (4)
Z = 2 (by substituting y = - 1, z = 2 into (1), we get
5x=6-2+1=5
x=1

It is known that the function y = f (x) with continuous image has a unique zero point in the interval (a, b) (B-A = 0.1). If the approximation of the zero point (accurate to 0.000 & nbsp; 1) is obtained by dichotomy, then the number of times to divide the interval (a, b) equally is at most______ ．

Let n times be calculated, then n satisfies B − A2N = 0.12n ＜ 0.0001, that is, 2n ＞ 1000. Since 210 = 1024, 10 times of calculation can meet the requirements, so the number of times to divide the interval (a, b) is at most 10 times. So the answer is 10