As shown in the figure, in the parallelogram ABCD, the diagonal lines AC and BD intersect at point O, and the straight lines passing through point O intersect AD and BC at points m and N respectively. If the area of △ con is 2 and the area of △ DOM is 4, then the area of △ AOB is 2______ ．

As shown in the figure, in the parallelogram ABCD, the diagonal lines AC and BD intersect at point O, and the straight lines passing through point O intersect AD and BC at points m and N respectively. If the area of △ con is 2 and the area of △ DOM is 4, then the area of △ AOB is 2______ ．

∵ quadrilateral ABCD is a parallelogram, ∵ CAD = ∵ ACB, OA = OC, while ∵ AOM = ∵ NOC, ≌ con ≌ AOM, ≌ s △ AOD = 4 + 2 = 6, and ∵ ob = OD, ∵ s △ AOB = s △ AOD = 6

Solve the equation. (x + 8.2) × 2 = 40

Solution: x + 8.2 = 40 △ 2
x+8.2=20
x=20-8.2
x=11.8

Given the points a (- 3,5), B (2,15), find a point P on the straight line L: 3x-4y + 4 = 0 to minimize | PA | + | Pb |

In fact, if p 'is a point different from P on L, then | p' a | + | p 'B | = | p' a | + | p 'B | > a' a 'B | = |

If there is simple calculation, it is necessary to simply calculate 2x-3 / 3 / 1 = 1 and solve the equation quickly

13 of 7 * 11 of 8-3 of 7 * 13 of 8
=11 out of 7 * 13 out of 8-3 out of 7 * 13 out of 8
=13 out of 8 * (11 out of 7-3 out of 7)
=13 / 8 * 1
=13 out of 8
2x-3 / 2x-1 / 3 = 1
X-2X/3=1+1/3
X/3=4/3
X=4

It is proved by collocation method that the value of - 8x ^ 2 + 8x-12 is always negative no matter what the real number of X is, and the maximum value of this formula is obtained when the value of X is obtained

Original formula = - 8x ^ 2 + 8x-12
=-8(x*2-x)-12
=-8(x*2-x+1/4)-12+2
=-8(x-1/2)^2-10
∵（x-1/2）^2≥0
∴-8（x-1/2）^2≤0
The original formula is less than 0
To maximize the original, then - 8 (x-1 / 2) ^ 2 should be minimized
If (x-1 / 2) ^ 2 is the smallest, then x = 1 / 2
The original formula max = 0-10 = - 10

If the inverse half of x minus two times the reciprocal of the difference of - 2 is 1, the equation is___________

The opposite number of X - half of the opposite number of x 1 / 2 (- x) half of the opposite number of x minus the difference of - 2 1 / 2 (- x) - (- 2)
The inverse half of x minus the reciprocal of - 2 is 1
2 *1/{1/2(-x)-(-2)} =1

The polynomial: X5 - (- 4x4y + 5xy4) - 6 (- x3y2 + x2y3) + (- 3y5) is arranged in descending order of the letter X after removing the brackets______ ．

x5-（-4x4y+5xy4）-6（-x3y2+x2y3）+（-3y5）=x5+4x4y-5xy4+6x3y2-6x2y3-3y5=x5+4x4y+6x3y2-6x2y3-5xy4-3y5．

We can't use dichotomy to find the zero point of a function
We can't use dichotomy to find the zero point of a function of degree?
What are the conditions for finding the zero point of a function by dichotomy? Who can give me an accurate answer to this question? Thank you very much!

For the function f (x), we first find that a and B belong to the interval (x, y), so that f (a) and f (b) have different signs, indicating that there must be zero in the interval (a, b),
Therefore, dichotomy requires that there are at least two points in the definition field corresponding to the value of F (x), and the sign is opposite, that is, for the quadratic function △ = B & # 178; - 4ac > 0, dichotomy can be used

It is known that the parabola y = x ^ 2 + BX + C has only one intersection with the X axis
(1) If the intersection is a (2,0), find the analytic formula of the parabola
(2) If the intersection of the parabola and the y-axis is B, the origin of the coordinate is O, and △ OAB is an isosceles triangle, find the analytical formula of the parabola, and explain how it is obtained from the translation of the parabola in (1)?

Because B (0, c), a (- B / 2,0), that is, | C | = | - B / 2 |, we can get b = 0 (△ OAB does not exist, rounding) or B = ± 2, C = 1y = x ^ 2 + 2x + 1, along the X axis

Parabola y = ax square + 2 has the same shape as parabola y = - 2x square - 1, so how to find the value of a?
If the shape of parabola is the same, is a equal or the absolute value of a equal?

The sign of a affects whether the opening direction of the curve is up or down. The absolute value of a affects the shape of the curve