Triangle, center of gravity, center, perpendicular, inner, outer. What do you mean

Triangle, center of gravity, center, perpendicular, inner, outer. What do you mean

The center of gravity is the intersection of the three midlines
The perpendicular is the intersection of the three heights
The heart is the intersection of three bisectors
The outer center is the intersection of the vertical bisectors of the three sides
The center is only a regular triangle. If the center of gravity, vertical center, inner center and outer center of a regular triangle coincide, this point is the center

What does ^ in (- 8) ^ 5 mean?

^Is: power, ^ 5 is power 5

How to calculate 7.23 + 6.84-0.84 + 2.77?

7.23+6.84-0.84+2.77
=(7.23+2.77)+(6.84-0.84)
=10+6
=16

If the difference between the polynomials 3x & # 178; + ax-2y & # 178; + 1 and 2bx & # 178; - 3xy + Y & # 178; has nothing to do with the value of X,
Find the value of algebraic formula 2 (A & # 178; - 2Ab + B & # 178;) - 3 (B & # 178; - A & # 178;)?

Difference = 3x & # 178; + ax-2y & # 178; + 1-2bx & # 178; + 3xy-y & # 178;
=(3-2b)x²+(a+3)xy-3y²+1
If it is independent of X, the coefficient of the term containing x is 0
3-2b=0,a+3=0
a=-3,b=3/2
So the original formula = 2A & # 178; - 4AB + 2B & # 178; - 3B & # 178; + 3A & # 178;
=5a²-4ab-b²
=45+18-9/4
=243/4

Prove that the sum of exterior angles of triangle is equal to 360 degrees

Let the three inner angles of a triangle be a, B and C respectively, and the corresponding outer angles are A1, B1 and C1 respectively
Obviously
A+A1=180
B+B1=180
C+C1=180
So the three formulas add up to a + A1 + B + B1 + C + C1 = 540
Because a + B + C = 180
So a1 + B1 + C1 = 540 - (a + B + C)
=360
That is, the sum of external angles is 360

The determinant that can be found? The first line: 2 1 / 3 4 - 3, the second line: 5 - 1 / 2 1 - 2, the third line: 3 1 / 4 2 - 5, the fourth line: - 4 10 5
First line: 2 1 / 3 4 - 3
Second line: 5 - 1 / 2 1 - 2
Third line: 3 1 / 4 2 - 5
The fourth line: - 4 10 5

2 1 / 3 4 35 - 1 / 2 1 - 23 1 / 4 25 - 4 10 5c2 * 12 [eliminate fraction, pay attention to multiply the final value of determinant by 1 / 12] 2 4 4 35 - 6 1 - 23 3 25 - 4 120 5 do r1-2r3, r3-2r1-4 - 20 - 75 - 6 1 - 2 - 7 150 9 - 4 120 5 expand (- 1) * - 4 - 2 - 7 15 9 according to the third column

Simple calculation: 78 out of 78 × 79, 200 out of 2008 × 2007

78 of 78 × 79 = (79-1) × 78 / 79 = 79 × 78 / 79-78 / 79 = 78-78 / 79 = 77 and 1 / 79
200 / 2008 × 2007 = (2007 + 1) × 200 / 2007
=2007 × 200 / 2007 + 200 / 2007 = 200 + 200 / 2007 = 200 and 200 / 2007

Find the limit 2 (x + 1) arctan (1 / x) close to 0

Primitive = {LIM (x - > 0) [2 (x + 1)]} * {LIM (x - > 0) [arctan (1 / x)]}
=2*(π/2)
=π

Simple calculation 16-6 * 0.54 + 1.66 * 3.6 + 1.66

16-6*0.54+1.66*3.6+1.66=16-6*0.54+1.66*（3.6+1）=20.396

-25A & # 178; + 50A factorization,

-25a²+50a
=-25a(a-2)