The maximum distance from the point on the curve X = 2cos θ y = sin θ (θ is the parameter) to the origin is () A. 1B. 2C. 2D. 3

The maximum distance from the point on the curve X = 2cos θ y = sin θ (θ is the parameter) to the origin is () A. 1B. 2C. 2D. 3

The distance from the point on the curve X = 2cos θ y = sin θ (θ is a parameter) to the origin is 4cos 2 θ & nbsp; + sin 2 θ = 1 + 3cos 2 θ ≤ 2, if and only if cos θ = ± 1, the maximum value is obtained, so C
Find ellipse x=4+2cos@y=1+5sin The focal length of
cos²φ+sin²φ=1
So (x-4) & #178 / 4 + (Y-1) & #178 / 25 = 1
So a & # 178; = 25, B & # 178; = 4
c²=25-4=21
So focal length = 2C = 2 √ 21
The parameter equation of the ellipse is known as x = 2 √ 2cos θ, y = √ 5sin θ (θ is the parameter), and the point P (2, - 1) in the ellipse is the center
It is known that the parameter equation of an ellipse is x = 2 √ 2cos θ, y = √ 5sin θ (θ is the parameter), and the linear equation of the chord with point P (2, - 1) as the midpoint in the ellipse is obtained
a=2√2,b=√5
x^2/8+y^2/5=1
Through P (2, - 1) straight line: y + 1 = K (X-2)
5x^2+8y^2=40
5x^2+8[k(x-2)-1]^2=40
5x^2+8k^2(x-2)^2-16k(x-2)+8=40
(5+8k^2)x^2-(32k^2+16k)x+(32k^2+32k-32)=0
x1+x2=(32k^2+16k)/(5+8k^2)
(x1+x2)/2=2
(32k^2+16k)/(5+8k^2)=4
8k^2+4k=5+8k^2
4k=5
k=5/4
y+1=(5/4)(x-2)
y=5x/4-7/2
Xiao Ming's father works four days and has one day off. Xiao Ming's mother works two days and has one day off. Xiao Ming has one day off on Saturday and Sunday,
The whole family will have a rest on Saturday, August 5. When will they have a rest next time? You can't write the answers directly. You should have a formula instead of an equation
His father had a fifth day off
His mother is off for the third day
Xiao Ming is on the sixth and seventh day off
Find their common divisor
Xiao Ming has a rest on Sunday on the 15th day
Because August 6 is Sunday, Xiao Ming's common divisor algorithm adds one more day, which is 1 + 7X2 = 15
His father 5x3 = 15
His mother 3x5 = 15
So they're off at the same time, August 20
This is a primary school problem. I haven't done such a math problem for more than 20 years. At that time, my math was the top three in my class. Now I can only barely answer you
What is the conversion relationship between air conditioning power and XX HP?
The relationship between power and watt in input power is: 1p = 735w. Power in air conditioning refers to cooling capacity, not electric power. Generally, 1p: 2300w-2500w, 1.5p: 3000w-3600w, 1.25p: 2600w-2800w, 2p: 4000w-5200w, 3P: 6500w-7200w
Adopt
Why is the ampere molecular current hypothesis wrong?
Molecules are made up of atoms with electrons moving around the nucleus. So how does this refute the ampere molecular circulation hypothesis?
Of course, it's wrong. But for those who only know classical physics, this hypothesis is helpful to a rough understanding of the problem to a certain extent
The motion of an electron in an atom is not a circular motion at all, so there is no trajectory. The motion around the nucleus can only be understood as a random motion outside the nucleus, but the average effect of this motion is similar to that of circular motion, Thus, ampere hypothesis can explain the experimental facts to a certain extent. It can be considered that ampere hypothesis is a rough approximation of quantum mechanics
If you have any questions, please ask
The answer is 48
7×7-7÷7=48
7*7-（7/7）=49-1=48
7×7－（7÷7）=48
7*7-7/7
What day do you want to visit the museum? Xiao Hong's mother works for 4 days and has 1 day off. Xiao Hong's father works for 2 days and has 1 day off. Xiao Hong has Saturdays and Sundays off. Xiao Hong, her mother and her father work for 2 days; Xiao Hong, her mother and father will have a rest on July 3. They will go to see their grandfather together. They will visit the museum on the next day when they have a rest at the same time. What's the date of visiting the museum?
The least common multiple of 3 and 5 is 15, 2 + 15 = 17, July 17 is Sunday, that is, they have a rest to visit the museum on July 17
How many kilowatts is 1.5pi air conditioner? How to convert
Is there a formula
The so-called "power" of an air conditioner originally refers to the input power, including the compressor, fan motor and electric control part. The cooling capacity is calculated by the output power. Generally speaking, the cooling capacity of one power is about 2000 kcal, which should be multiplied by 1.162 when converted into international units. Therefore, the cooling capacity stress of one power is 2000 kcal x1.162 = 2324 (W), where w (W) is the cooling capacity, In general, 2200w-2600w can be called 1p, 4500 (W) - 5100 (W) can be called 2p, 3200w-3600w can be called 1.5p
One horse is about 736 watts
According to the molecular current hypothesis, ampere well explains why the phenomenon of electromagnetic induction is wrong
Electromagnetic induction was discovered by Faraday, which is the principle of magnetic generator
Ampere explains the ampere force according to the molecular current hypothesis, that is, the phenomenon that the charged conductor is forced in the magnetic field