1000 divided by 50

1000 divided by 50

twenty

Simple formula for the sum of the first n terms in Mathematics
A1 = 2 A2 = 4 A3 = 6 A4 = 12 A5 = 24 A (n) = 2 * a (n-1)
All of a sudden, confused, who can help me solve the formula of this sequence, I am really depressed
Wrong, a (n) = 2 * a (n-1) a > 3
In fact, a (n) = a (n-1) + a (n-2) + a (n-3) + a（2）+a（1）

It seems very complicated. In fact, the first two terms are equal ratio sequence with 2 as the first term and 2 as the common ratio. From the third term, the sequence is equal ratio sequence with 6 as the first term and 2 as the common ratio. As for the sum of the first n terms, it can be obtained from the sum formula of the first n terms of the equal ratio sequence. When n is less than 3, Sn = 2 ^ (n + 1) - 2; when n is greater than or equal to 3, Sn = 3 * 2 ^ (n + 1), where 2 ^ (n + 1) represents the N + 1 power of 2
The sum formula of equal ratio sequence is Sn = A1 * (1-Q ^ n) / (1-Q), where Q ^ n is the nth power of common ratio Q

37°28′＋44°49′＝ 108°18′－52°30″＝ 25°36′×4＝ 40°40′÷3＝

37°28′＋44°49′＝(37°+44°)(28'+49')=81°77′=82°17’
108°18′－52°30″＝(108°-52°)17'(60''-30'')=56°17'30''
25°36′×4＝(25°×4)(36'×4)=100°144'=102°24'
40°40′÷3＝(40°÷3)(40'÷3)=(40/3)°(40/3)'=13°33'20''

(A's Square - B's Square / A's Square - AB) divided by (a + A / 2Ab + B's Square)
Square A-Square b-square 2Ab + square B
——————Divide by (a + --)
A squared - AB a
I don't know how to score. Overall, thank you

Square A-B of (1-B) * (a + b)

I have a math problem in senior high school entrance examination. Who can help me do it
In the right triangle ABC, the angle c is equal to 90 °, D and E are the points on the extension line of CB and Ca respectively, and the intersection point of be and ad is p. if BD = AC and AE = CD, then the degree of angle ape is calculated

For afiicd, dfiiac, the intersection of the two is f ∵ angle c equal to 90 °, ACDF is a rectangle, CD = AF, AC = DF ∵ BD = AC, AE = CD ∵ BDF and △ AEF are isosceles right triangles, BF / DF = EF / AF = √ 2 ∵ ADF ∵ EBF ∵ PAF = ∠ PEF ∵ ape = ∠ AFE

2.4x-21 = x to solve the equation

2.4x-21=x
2.4x-x=21
1.4x=21
x=21÷1.4
x=15

51 and 4:1 * 61 and 5:1 * 6:5 + 71 and 6:1 * 7:6
Speed, speed, I'm waiting

(51 + 1/4)*(61 + 1/5)*5/6 + (71 + 1/6)*6/7 = 10699/4

The value of quadratic function y = AX2 + BX + C is nonnegative, and b > A is the range of a + B + C divided by b-a?

A, B, C ＞0, a, B, C, a, B, C, and B & sup2; - 4ac ≤ 0, and B & sup2; - 4ac ≤ 0, and B & sup2; - 4ac ≤ 0, and B & sup2; and B & sup2; - 4ac. = = = = = = (B \\\\\ \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\inother words, (a + B + C) / (B-A) > 2

Simple calculation
（1）10.26-（3.78+4.26）（2）2.4÷0.25（3）1.9x32x125x0.25

（1）10.26-（3.78+4.26）=10.26-3.78-4.26=10.26-4.26-3.78=6-3.78=2.22（2）2.4÷0.25=2.4÷1/4=2.4*4=9.6（3）1.9x32x125x0.25=1.9x8x4x125x0.25=1.9x8x125x0.25x4=1.9x1000x1=1900

It is known that the parabola y = - x square + 2mx-4m-x square (M is a constant) has two intersections with the X axis
It is known that the parabola y = - xsquare + 2mx - 4m - xsquare (M is a constant) has two intersections with the X axis
(1) When m is the largest integer, the analytical expression of parabola is obtained
(2) Let the vertex of the parabola be C, the axis of symmetry of the parabola intersects with the X axis at point B, the line y = - x + 3 intersects with the X axis at point a, point P is a moving point on the axis of symmetry of the parabola, passing through point P as PD ⊥ AC, and the perpendicular foot D is on the line AC. if s △ pad = 1 / 4 (s △ ABC), the coordinates of point P are obtained
Another problem: parabola y = ax ^ 2 + BX + C, if 2A + B = 0, and when x = - 1, y = 3, find the value of y when x = 3

The first question is not clear. Please see if it is wrong
Parabola y = ax ^ 2 + BX + C, if 2A + B = 0, and when x = - 1, y = 3, find the value of y when x = 3
2A + B = 0, which means that when the axis of symmetry is x = 1, x = - 1 and x = 3, the value of function is equal, and the value of Y is 3