Let vector a = (COS α, (λ - 1) sin α), vector b = (COS β, sin β), (λ > 0,0)

Let vector a = (COS α, (λ - 1) sin α), vector b = (COS β, sin β), (λ > 0,0)

a+b=(cosα+cosβ,(λ-1)sinα+sinβ)a-b=(cosα-cosβ,(λ-1)sinα-sinβ)∵a+b⊥a-b∴(cosα+cosβ)·（cosα-cosβ）+[(λ-1)sinα+sinβ]·[(λ-1)sinα-sinβ]=0∴(cosα)^2-(cosβ)^2+(λ-1)^2(sinα)^2-(sin...
2 / 3 of a number minus 7 equals 12. What's the number
（12+7）÷2/3=28.5
（12+7）÷2/3=28.5
(12+7)÷(2/3)=19×(3/2)=28.5
On a map with a scale of 1:6000000, the distance between the two places is 5cm, and two cars, a and B, travel from the two places at the same time,
Three hours later, the two cars met. It is known that car a travels 56 kilometers per hour and car B how many kilometers per hour
Distance = 5 × 6000000 = 30000000 cm = 300km
Vehicle B speed = 300 △ 3-56 = 44 km / h
Forty-four
The distance is 300km
Let the velocity of B be X
56*3+X*3=300
X=44KM
B 44 kilometers per hour!
5 * 6000000 = 30000000 cm = 300km; 300 / 3 = 100km / h
100-56=44Km
The total distance is 3 km, 300 △ 3-56 = 44 km
The distance between the two places is 6000000 * 5 / 100000 = 300km
Car a has driven 56 * 3 = 168 km, car B has driven 300-168 = 132 km, and car B has driven 132 / 3 = 44 km per hour.
Let a = (32, sin θ), B = (COS θ, 13), where θ ∈ (0, π 2). If a ‖ B, then θ = 0___ .
If a ∥ B, then sin θ cos θ = 12, that is, 2Sin θ cos θ = 1, ∥ sin2 θ = 1, and θ∈ (0, π 2), ∥ θ = π 4
A number of 16 times minus 25 is equal to 675, how to find the number formula
（675+25）÷16=175/4
16x-25 = 675, so x = 175 / 4
16x-25=675
16x-25=675
16x=675+25
16x=700
x=700/16
x=43.75
16x-25=675
Math problem: on a map with a scale of 1:6000000, the distance between a and B is 35cm. At 9:20 a.m., a plane took off from a place
At 11:50 a.m., the plane arrived at the second place. How many kilometers per hour does the plane fly? What's the process
What is the actual distance between a and B
35 △ 1 / 6000000 = 210000000 (CM) = 2100 (km)
From 9:20 a.m. to 11:50 a.m
11:50-9:20 = 2:30 = 2.5 hours
The plane flies every hour on average
2100 △ 2.5 = 840 (km)
Let a = (3 / 2, sin θ), B = (COS θ, 1 / 3), where 0
Vector A / / B,
Then cos θ / (3 / 2) = (1 / 3) / sin θ,
sinθ*cosθ=1/2,
sin2θ=1,
Because 0
Vector a = (3 / 2, SiNx), B = (cosx, 1 / 3). 0 < x < π / 2
∵ vector a ∥ b.. From the necessary and sufficient condition of vector collinearity, we can see that:
There is a real number T satisfying a = TB, that is: (3 / 2, SiNx) = t (cosx, 1 / 3)
When t is eliminated, we can get the following results: t cos x = 3 / 2 and SiN x = t / 3
3sinxcosx = 3 / 2. х sin (2x) = 1. And 0 ＜ x ＜ π / 2
∴2x=π/2. ∴x=π/4.
Vector a = (3 / 2, sin θ), B = (COS θ, 1 / 3), where 0
The difference of 3 times minus 5 of a number is equal to 2 times of the number. How to calculate the number? Can you say the basic principle and its formula in the most popular language? How to calculate the number when 5 times of a number is equal to the sum of 2 times of the number and 1.2? Can you say the basic principle and its formula in the most popular language?
Question 1, 3x-5 = 2x
3X-2X=5
X=5
The number is five
Question 2, 5x = 2x + 1.2
3X=1.2
X=0.4
This number is 0.4
Equation solution, assuming that number is x, and then according to the condition of the problem, the equation is set up. According to the principle that the equality of both sides of the equal sign is the same addition, subtraction, multiplication and division, the equation is solved and X is obtained
Question 1:
Let this number be x, we get 3x-5 = 2x, we get x = 5;
Question 2:
Let 2Y = 2.5Y = 1.5y.
The above equation is linear equation with one variable.
3x - 5 = 2x, then the number is 5
The difference between three times a number and five is equal to two times that number
It shows that three times of this number is the subtracted number, the subtracted number is five, and the difference is two times of this number
So, subtracted difference = subtracted, that is, three times of this number minus two times equals five, that is, this number equals five
Five times of a number is equal to the sum of two times of the number and 1.2,
Explain that five times of this number minus two times of this number equals 1.2, three times of this number equals 1.2, this number equals 0.43 times minus two times = 1, why is it equal to 5? Please say thank you. Three times minus two times equals one time
The difference between three times a number and five is equal to two times that number
It shows that three times of this number is the subtracted number, the subtracted number is five, and the difference is two times of this number
So, subtracted difference = subtracted, that is, three times of this number minus two times equals five, that is, this number equals five
And the sum of this number is 2.5 times the number,
Explain that 5 times of this number minus 2 times of this number equals 1.2, 3 times of this number equals 1.2, and this number equals 0.4? Please explain. Thank you
The distance between a and B is 400km. Car a goes from a to B, 60km per hour. Car B goes from B to a, 40km per hour
(1) if the two vehicles start at the same time, how long will they meet?
(2) If the two cars start at the same time and a car stops for half an hour on the way for maintenance before meeting again, how far is the distance between the two cars to a place
(1) 60x + 40x = 400, x = 4 hours a: meet in 4 hours
(2) At this time, a and B meet each other in 1603 hours. If a and B travel in 1603 hours, then a and B have to walk for another 30 hours,
The distance between the two vehicles is 210 + 18 = 228km
(1) 400÷(60+40)=4(h);
(2) (400-40×0.5)÷(60+40)×60=288(km)/
(1) Encounter time = distance △ speed and
If the two vehicles start at the same time, 400 (60 + 40) = 4 (hours) meet.
(2) Half hour B: 40 × 0.5 = 20 (km)
Encounter time: (400-20) △ 60 + 40 = 3.8 (hours)
The distance between vehicles and ground a: 60 × 3.8 = 228 (km)
Let vector a = (3 / 2, sin α), vector b = (COS α, 1 / 3), and vector a ‖ vector B, find the value of α
Vector a, B = (1 / s), and vector A / b = (1 / s),
So 3 / 2 * 1 / 3 = sin α cos α, 1 = 2 sin α cos α
sin2α=1
So α = π / 4 + K π K ∈ Z