The polar coordinate equation of the circle with the center of (1, π / 2) and radius of 1 is? The answer is p = 2Sin θ,

The polar coordinate equation of the circle with the center of (1, π / 2) and radius of 1 is? The answer is p = 2Sin θ,

You draw a polar coordinate system. Draw a circle with diameter OA = 2 through pole o
Take any point P (ρ, θ) on the circle (preferably on the right side of the diameter). Connect Po, then ∠ XOP = θ, Op = ρ
In the right triangle OPA, OA = 2, Op = ρ, ∠ Pao = θ,
∴ρ＝2sinθ.
Explain the curve ρ = cos θ represented by the following polar equation
ρ=cosθ
ρ²=ρcosθ
x²+y²=x
(x-1/2)²+y²=1/4
This should be a circle. If you think about it, ρ represents the length from the pole (i.e. the origin) to any point on the curve in polar coordinates. The range of cos θ is [- 1,1], and ρ = cos θ, then the range of ρ is [0,1], so it must be a circle with diameter (maximum length) of 1
Is a circle, polar coordinates and rectangular coordinates of the conversion formula can be.
Change to rectangular coordinates x = cos & # 178; θ, y = cos θ sin θ
So Cos2 θ = 2cos & # 178; θ - 1 = 2x-1
sin2θ=2sinθcosθ=2y
From cos & # 178; (2 θ) + Sin & # 178; (2 θ) = 1
(2x-1)²+(2y)²=1, x∈[0, 1]
This is an ellipse
X ∈ [0,... Expansion
Change to rectangular coordinates x = cos & # 178; θ, y = cos θ sin θ
So Cos2 θ = 2cos & # 178; θ - 1 = 2x-1
sin2θ=2sinθcosθ=2y
From cos & # 178; (2 θ) + Sin & # 178; (2 θ) = 1
(2x-1)²+(2y)²=1, x∈[0, 1]
This is an ellipse
X ∈ [0,1] can not be marked, because even if it is not marked, x will not take the number outside this interval, but it is better to mark it
A car, with a mass of 2000 kg and a rated power of 80 kW, has a resistance of 0.1 times the weight of the car when driving on a straight road. If the car starts from a standstill with a uniform acceleration of 1, after reaching the rated output power, the car keeps the rated output power unchanged, accelerates for 800 meters to reach the maximum speed, and then runs at a uniform speed, 1. The maximum driving speed of the vehicle. 2. The time from the rated output power to the maximum driving speed of the vehicle
1、P=F1*V F1-f=ma F=2m v=20m/s
at1=v t1=20s
P=F2V2=mV2 V2=40m/s
2、 Pt2=m(v2²-v1²）/2+f*s=m/2(v2+v1)(v2-v1)+ma*800
t2=35s
The maximum speed is traction force = friction resistance, and then according to the conservation of energy
Vmax = P / F = 32. Ranletter}
1 hectare is equal to how many mu? I can't remember, ha ha
1 ha = 10000 m2, 1 mu = 666.67 M2 - > 1 ha = 15 mu
Four operation rules of derivative, partial derivative formula, derivative method under integral sign
Four algorithms of derivative (sum, difference, product and quotient)
①(u±v)'=u'±v'
②(uv)'=u'v+uv'
③(u/v)'=(u'v-uv')/ v^2
Derivation method under integral sign
d(∫f(x,t)dt φ(x),ψ(x))/dx=f(x,
ψ(x))ψ'(x)-f(x,φ(x))φ'(x)+∫[f 'x(x,t)dt φ(x),ψ(x)]
Derivative is an important pillar of calculus. Newton and Leibniz made outstanding contributions to it!
Z Xiaoqiang Xiaogang has more than 100 stamps. If Xiaoqiang gives Xiaogang x stamps, Xiaoqiang will be 60% less than Xiaogang. If Xiaogang gives Xiaoqiang x stamps, Xiaogang will be 37.5% less than Xiaoqiang. How many stamps are there for each of them?
Let Xiaogang have a cartoon, Xiaoqiang give Xiaogang X: Xiaogang now has (a + x), because Xiaoqiang's cartoon is three seventh less than Xiaogang's, so Xiaoqiang's cartoon is: 3 / 7 (a + x), Xiaogang give Xiaoqiang X: Xiaogang now has (A-X), because Xiaogang's cartoon is three tenth less than Xiaoqiang's, so
The rated power of the automobile engine is 60 kW, the mass of the automobile is 5 tons, the automobile runs on the horizontal road
The rated power of the automobile engine is 60 kW, the mass of the automobile is 5 tons, and the resistance of the automobile is 0.1 times of the vehicle weight when driving on the horizontal road. How much is the maximum speed that the automobile can reach after starting from a standstill while maintaining the rated power? How long can the process last when the automobile starts from a standstill and keeps the acceleration of 0.5 m / S2?
A small ball with a mass of 0.1kg moves from the rough horizontal ground to a smooth semicircle track with a radius of 0.4m at an initial speed of 7m / s. The point at which the ball hits the semicircle track is point a. the ball decelerates at a = 3m / S2 on the ground. After the ball moves 4m, it hits the semicircle. Finally, the ball falls at point C to calculate the distance of AC
1. When reaching the maximum speed V, the car only works against the resistance P = FV v = P / F P = 60000w f = 5000n
V=12m/s
2 F = ma = 5000 * 0.5 * 10 = 25000n f '= 5000n f = 30000N maximum speed of uniform acceleration V' = P / F = 2m / s t = V '/ a = 4 S
First, judge whether the speed of the ball can reach the highest point. If the speed of the ball can't reach the highest point, return to it. Use the law of conservation of energy to find out whether the ball can reach the highest point and then do the horizontal throwing motion. Then use the formula of horizontal throwing motion to find out
Who can tell me how much square an acre is equal to
Refer to WM smartphone tool: smart measurement unit converter, mu, also known as city mu, is the land area unit of China's municipal system. There are acres in British and American system, and acres in metric system. 1 city Mu = 666.666... Square meters (M2) 1 hectare = 100 square meters (M2) 1 acre = 4046.8564224 square meters (M2) log in to China Unicom Wo store (www.unicom.com)_ Address: store.wo.com There are screenshots and more detailed instructions for reference
One mu land = 666 2 / 3 square meters ≈ 666.7 square meters
Is the meaning of the four arithmetic operations of integers the same as the calculation method?
No! Absolutely different
Because law is an operation method, but meaning is the meaning of this operation
Xiaoliang has 48 cartoons, and Xiaogang's cartoons are 8 / 3 less than Xiaoliang's. how many cartoons do Xiaoliang and Xiaogang have?
48 divided by 8 = 6 48-6-6 = 30 48 + 30 = 78 A: there are 78 pieces in total, isn't it 3 / 8
Total 48x (1 + 8 / 3) = 176