The chord length is 8 meters, the chord center to the highest point of the arc is 3 meters, find out the arc length Chord length, H Gao Xianqiu Please explain your ideas for you

The chord length is 8 meters, the chord center to the highest point of the arc is 3 meters, find out the arc length Chord length, H Gao Xianqiu Please explain your ideas for you

The idea of this problem should be as follows: in order to get the arc length of the bow, we must know the radius (diameter) of the circle where the bow is located and the central angle of the circle to which the arc is opposite

Why is Tan (45 ° - α) equal to (tan45 ° - Tan α) / (1 + tan45 ° × Tan α)?
RT

Because Tan (a + b) = (Tana + tanb) / (1-tana * tanb)
tan(a-b)=(tana-tanb)/(1+tana*tanb)

Cos (arcsinx) = √ 1-x ^ 2 what else is there in a formula like this?
cos(arcsinx)=√1-x^2
What else is there in a formula like this?
sin(arccosx)=?
sin(arctanx)=?
sin(arcsinx)=?
cos(arctanx）=?
tan(arctanx)=?

Let arccosx = y, then x = cosy, y ∈ [0, π], so siny > = 0, siny = root sign (1-cos ^ 2, y) = root sign (1-x ^ 2), which proves that sin (arccosx) = root sign (1-x ^ 2)
Similarly,
Sin (arctanx) = x / radical (1 + x ^ 2)
sin(arcsinx)= x
Cos (arctanx) = 1 / radical (1 + x ^ 2)
tan(arctanx)= x
A few more
arcsinx+arccosx=π/2
arctanx+arcctanx=π/2
In addition, there are identities of arcsecx and arccscx, which are not listed here

How to get the value of COS (arcsinx)?
The answer can be expressed by X

"√" is the root sign and "^" is the square sign
Because: - π / 2 ≤ arcsinx ≤ π / 2
cos(arcsinx)=√[(1-sin^(arcsinx)]=√(1-x^2)

How to transform cos (arcsinx)?

Let z = arcsinx
Then x = Sinz = x / 1 = opposite / hypotenuse, adjacent = √ (1-x & # 178;)
Cos (arcsinx) = cosz = adjacent / hypotenuse = √ (1-x & # 178;) / 1 = √ (1-x & # 178;)

What's the meaning of "Che Ba Ping 6", "will 4 go into 1", "Ma 2 go back 4", "Che 2 go into 8", "Che 7 go back 6", "Che 2 Ping 8"

Red chessboard from right to left longitudinal nine vertical lines marked as one to nine
The vertical line from right to left in black is 1 to 9
The red way is the black way
1、 A chess piece in a straight line
Advance and retreat are grid counting
For example, one step forward of Hongfang road is one step forward
Ping is to record how many routes to go from
From paoping to Wulu of Hongfang No.2 is paoping No.5
2、 The chessmen with oblique line only advance and retreat, not even
Advance and retreat is to record how many routes to go from
For example, if the horse on the second route jumps forward to the third route, the horse on the second route enters the third route
If there are two identical pieces on the same path, they are distinguished by the front and back, and it is not necessary to indicate the path
For example, on the second road, there are two cars in front of us. One step forward is one step forward

Who is the closest to this problem? I'll give him all the points: 5 + 6 + 4 + 0 + 3 + 6 + 10 + 8 +... + x-8-10-6-7-6 -... - x = (- 10)

Everyone's thinking is different. It depends on how you look at the problem. As long as your own ideas are correct, there is no standard answer to this question~

Idioms with the character of horse: 1. Flat terrain 2. Great momentum 3. Speed up 4. Walk in the forefront 5. Many people 6. Roughly look 7. Make contributions 8. Act alone 9. Very dangerous 10
I'll go
Just walk around

The terrain is flat
Great momentum: ten thousand horses galloping
Speed up: speed up
Take the lead
Five men and many horses
A cursory view
7. Thanks: Thanks a lot
8 acting alone: alone
9 very dangerous: rein in the precipice
10. Walk at will

The known point P is an arc x = 4cos α, y = 4sin α (0

This is a semicircle with a radius of four
The op line is y = Tan θ * X
Q(4/tanθ,4)
p(4cosθ.4sinθ)
m(2/tanθ+2cosθ,2+2sinθ)
Find the relationship between 2 / Tan θ + 2cos θ and 2 + 2Sin θ
The parameter equation is
x=2/tanθ+2cosθ
y=2+2sinθ
0＜θ＜π

Find the value of function y = 7-4sin (x) cos (x) + 4cos ^ 2 (x) - 4cos ^ 4 (x)

y=7-4sin(x)cos(x)+4cos^2(x)-4cos^4(x)
=7--4sin(x)cos(x)+4cos^2(x)sin^2(x)
=7-2sin(2x)+sin^2(2x)
=(sin(2x)-1)^2+6
=6