(2x-3) &# 178; = 49 solution equation

(2x-3) &# 178; = 49 solution equation

2x-3=±7
2X = 10 or - 4
X = 5 or - 2
Find the polar equation of the following curve
A line passing through point a (3, π / 3) parallel to the polar axis
A line passing through point B (- 2, π / 4) perpendicular to the polar axis
A circle whose center is at point a (5, π) and radius is equal to 5
4 passes through a circle with radius equal to 5 at point C (a, 0)
This kind of questions are usually done by the transformation of polar coordinates and rectangular coordinates (because they are not familiar with polar coordinates and are familiar with rectangular coordinates)
X=ρ*COSθ,Y=ρ*SINθ,ρ^2=X^2+Y^2
Of course, it can be done directly (for example, the first question)
You can build a right triangle to do it, as long as you find the quantity (e.g. D of the first question)
The polar axis of the line (3) passing through π / 1
The straight line is parallel to the polar axis, and the distance D is: 3 * sin60 = 3 √ 3 / 2
So: D / ρ = sin θ
Linear polar coordinate equation: 3 √ 3 / 2 = ρ * sin θ
A line passing through point B (- 2, π / 4) perpendicular to the polar axis
It is transformed into a rectangular coordinate system, that is, it passes through the point (- √ 2, √ 2) and is perpendicular to the x-axis
So line = - 2
To polar coordinate equation: ρ * cos θ = - √ 2
A circle whose center is at point a (5, π) and radius is equal to 5
It is also changed into rectangular coordinate system, that is: center a = (0, - 5), radius = 5
So the equation: (x-0) ^ 2 + (y + 5) ^ 2 = 5 ^ 2
ρ ^ 2 + = cos * 25
ρ^2*COS^2θ+ρ^2*SIN^2θ+25+10ρ*SINθ=25
ρ^2*COS^2θ+ρ^2*SIN^2θ+10ρ*SINθ=0
ρ^2*1+10ρ*SINθ=0
ρ+10SINθ=0
4 passes through a circle with radius equal to 5 at point C (a, 0)
To rectangular coordinate system: C = (a, 0), radius = 5
Rectangular coordinate equation: (x-a) ^ 2 + y ^ 2 = 5 ^ 2
It is reduced to polar coordinate equation: (ρ ^ 2 * cos ^ 2 θ - 2A ρ * cos θ + A ^ 2) + ρ ^ 2 * sin ^ 2 θ = 25
ρ^2*1-2aρ*cosθ+a^2-25=0
Explain what curve the following polar coordinate equation θ = 5 π / 6 represents and draw a diagram
Denotes a ray with the coordinate origin as the endpoint and the inclination angle of θ = 5 π / 6
If you know what it is, you can draw it yourself
θ = 5 π / 6 is the ray passing through the origin, and the angle is 5 π / 6
It's a straight line, because P can take R, which is a straight line y = - root 3 / 3x
I won't draw that picture
The laws of addition are as follows______ And______ .
The operation law of addition includes commutative law of addition and associative law of addition
A computing device has a data entry a and an operation result exit B. the following table is the result obtained by Xiaogang after inputting some numbers
A 0 1 4 9 16 25 36
B -2 -1 0 1 2 3 4
(1) If the output number is 5, what is the input number?
(2) If the input number is 225, what is the output number?
By observing the data, we can find: group a data: 0, 1 = 1 & # 178;, 4 = 2 & # 178;, 9 = 3 & # 178;, 16 = 4 & # 178;, 25 = 5 & # 178;, 36 = 6 & # 178; ··· n & # 178; ·· group B data: - 2, - 1 = - 2 + 1 * 1, 0 = - 2 + 2 * 1, 1 = - 2 + 3 * 1, 2 = - 2 + 4 / 1, 3 = - 2 + 5 * 1, 4 = - 2 + 6 * 1
How many amperes is a kilowatt
If it is a 220V 1000W electrical appliance, I = 1000W / 220V = 4.545a
(1) 2 square meters=______ Square decimeter (2) 5 square decimeter=______ Square centimeter (3) 400 square decimeter=______ Square meters (4) 900 square centimeters=______ Square decimeter (5) 1 square meter=______ Square decimeter=______ Square centimeter (6)______ Square meter = 600 square decimeter=______ Square centimeter
(1) 2 square meters = 200 square decimeters; (2) 5 square decimeters = 500 square centimeters; (3) 400 square decimeters = 4 square meters; (4) 900 square centimeters = 9 square decimeters; (5) 1 square meters = 100 square decimeters = 10000 square centimeters; (6) 6 square meters = 600 square decimeters = 60000 square centimeters
Which operation laws are applied to the following formulas?
25×（6＋8）=25×14
Combination law of distribution rate
A computing device has a data entry a and an operation result exit B. the numbers in the natural number are input into port a in turn, and the output numbers are obtained from port B. The results show that: (1) when n = 1 is input from port a, A1 = 13 is obtained from port B; (2) when n ≥ 2, n is input from port a, and the result obtained from port B is that the previous result an-1 is multiplied by the natural number and the n-1st odd number, and then divided by the natural number And the N + 1 odd number, ask: (1) when inputting 2 and 3 from port a, what numbers do you get from port B? (2) When inputting 2008 from port a, what number do you get from port B? (3) Ask: a1 + A2 + a3 +The value of A2008
(1) According to the meaning of the title: A2 = A1 × 15 = 13 × 15 = 12 × 2 − 1 × 12 × 2 + 1 = 115, A3 = 12 × 3 − 1 × 12 × 3 + 1 = 135; (2) observe the law of (1): A2008 = 14015 × 14017 = 116128255; (3) find out the general form as: an = 12 (12n − 1-12n + 1), 〈 a1 + A2 + a3 + A2008 = 12 (11-13 + 13-15 + -14017）=12×40164017=20084017．
How many joules is a thousand watt hours
No,
MWh = 1000W * 3600s = 3.6 * 10 ^ 6J