The relationship between the slope of focus chord and the ratio of focus chord and eccentricity of conic curve? RT

The relationship between the slope of focus chord and the ratio of focus chord and eccentricity of conic curve? RT

Let the included angle be Θ, k = Tan Θ, and the ratio of points be: λ = (1 + ecos Θ) / (1-ecos Θ)

As shown in the figure, O is the intersection of diagonal lines of rectangular ABCD, AE bisects ∠ bad, ∠ AOD = 120 ° and calculates the degree of ∠ AEO

AOD = 120 and 186; AOB = 180 and 186; AOB = 180 and 186; - 120 and 186; - 120 and 186; = 60 and 186; and the #;;; AOB is an equilequilequilequilequiltriangle; AOB is an equilequilequilequilequilequilequiltriangle; ABO = 60; ABO = 60; ABO = 90; OBE = 90 and 90; OBE = 90; 90; OBE = 90; OBE = 90; OBE = 90; OBE = 90; be = 50; AE equal division of bad, bad, bad, bad = 90, as 90 \\\ \\\\\\\\\\\\\\\\\\and

The propagation speed of light in vacuum is 3 × 10 8 m / s. The distance between the sun and the earth is 1.5 × 10 8 km. How many seconds can the light from the sun reach the earth

1.5 × 10 ^ 8 × 10 ^ 3 △ 3 × 10 ^ 8 = 500 seconds
The light from the sun reaches the earth in 500 seconds

If you make a long-distance call from a to B, you will be charged 2.4 yuan for a call within 3 minutes. After 3 minutes, you will be charged 1 yuan for each additional minute of call time. Find out the function of the change

Is a piecewise function: y = 2.4 × 3x (0 < x 3) thank you!

As shown in the figure, the quadrilateral ABCD is a square, the diagonal AC and BD intersect at O, Mn ‖ AB, and intersect at M and N with AO and Bo respectively. The proof is: (1) BM = CN; (2) BM ⊥ CN

In △ ABM and △ BCN, in △ ABM and △ BCN, in △ ABM and △ BCN, ab = BC, ab = BC, in △ ABM and △ BCN, ab = BC, in △ ABM and △ BCN, in △ ABM and △ BCN, in △ ABM and △ BCN, ab = BC, ab = BC, ab = BC, mAb = NBCAM = NBCAM = NBCAM = BN, and △ ABM ≌ delta BCN (SAS), BCN (SAS), BM = CN. (2) from △ ABM ≌ m ≌ B ≌ m ≌ from ≌ B ≌ BCN, from ≌ BCN, from ≌ BCN, from ≌ ABM ≌ B ≌ B ≌ BCN, from ≌ CBM = 90 °, 〈 BCN + ∠ CBM = 90 °, 〈 cn ⊥ BM

The mass of a carbon atom with six protons and neutrons is 1.993 × 10 to the negative 26th power, the relative mass of an oxygen atom is 16, and that of another oxygen atom is 16
What's the mass of the other oxygen atom?
There are options
A. 16 b, 16 G C, 12 × 16 × 1.993 × 10 minus 26 kg D, 1.993 × 16 × 10 minus 26 / 12 kg D

Select d according to the proportion, the relative mass of oxygen atom / the relative mass of carbon atom = the mass of oxygen atom / the mass of carbon atom

A and B start from two places at the same time and travel in opposite directions. The road becomes 900 kilometers. The speed ratio of a and B is 2:3. After 6 hours, they meet and the speed of a and B is 2:3
What are the degrees?

Car a per hour: 900 △ 6 × 2 / (2 + 3) = 60 (km)
Vehicle B per hour: 900 △ 6 × 3 / (2 + 3) = 90 (km)

If the first side of a triangle is (a + 2b) cm, the second side is (b-2) cm longer than the first side, and the third side is 5cm shorter than the second side, calculate the perimeter of the triangle

Let the lengths of the first, second and third sides be a, B and C
A=a+2b```````````①
B=A+(b-2)````````②
C=B-5````````````③
① B = a + 3b-2 'is obtained by substituting 2
④ C = a + 3b-7 'is obtained by substituting 3
Perimeter = a + B + C = 1 + 4 + 5 = 3A + 8b-9

·Given that a, B, C are positive integers and satisfy a ^ 2-B ^ 2-C ^ 2 = ABC, a ^ 2 = 2 (B, c), find the value of a, B, C
thank you
a^2=2(b+c)

a^2-b^2-c^2-2=-(b-1)^2-(c-1)^2=abc-2
It's 2-abc = (B-1) ^ 2 + (C-1) ^ 2
The right side must be positive, so ABC

At 14:48 Beijing time on May 12, a strong earthquake with magnitude 8 occurred in Wenchuan County, Sichuan Province (31 degrees north latitude and 103.4 degrees east longitude), causing huge losses of people and property. Huangshi also felt the earthquake. During the earthquake, the vibration of the source propagated outward in the form of S-wave and P-wave, and the propagation speed of the two waves in the crust was different, about 3.4km/s and 5.1km/s respectively The place where the earthquake is located is called the epicenter (as shown in the figure). The first place to reach the ground is the P-wave. At this time, people in the epicenter will feel up and down turbulence, and then the S-wave will come, and they will feel left and right sway. If the time difference between P-wave and S-wave arriving at the epicenter is 2 seconds, then how many kilometers is the distance from the source to the epicenter?

From the velocity formula: v = st, time: T = SV, let the distance from the epicenter to the source be s, according to the meaning of the question: s3.4km/s-s5.1km/s = 2S, the solution is: S = 20.4km; answer: the distance from the source to the epicenter is about 20.4km