Given the equation sin (A-3 π) = 2cos (A-4 π), find [sin (π - a) + 5cos (2 π - a)] / [2Sin (3 π / 2-A) - sin (- a)] There is no periodic function

Given the equation sin (A-3 π) = 2cos (A-4 π), find [sin (π - a) + 5cos (2 π - a)] / [2Sin (3 π / 2-A) - sin (- a)] There is no periodic function

Sin (A-3 π) = 2cos (A-4 π) can be reduced to sin (4 π + A-3 π) = 2cos (4 π + A-4 π), that is sin (π + a) = - Sina = 2cosa [sin (π - a) + 5cos (2 π - a)] / [2Sin (3 π / 2-A) - sin (- a)] = [Sina + 5cosa] / [- 2cosa + Sina] = 3cosa / - 4cosa = - 3 / 4
The periods of sin and COS are both 2 π
So sin (A-3 π) = sin (a + π) = - Sina
2cos(a-4π)=2cosa
So Sina = - 2cosa
[sin(π-a)+5cos((3π/2)-a)]/[2sin(3π/2+a)-sin(-a)]
=[sina+5cos(π+(π/2)-a)]/[2sin(π+π/2+a)+sina]
=[sina-5co
The periods of sin and COS are both 2 π
So sin (A-3 π) = sin (a + π) = - Sina
2cos(a-4π)=2cosa
So Sina = - 2cosa
[sin(π-a)+5cos((3π/2)-a)]/[2sin(3π/2+a)-sin(-a)]
=[sina+5cos(π+(π/2)-a)]/[2sin(π+π/2+a)+sina]
=[sina-5cos((π/2)-a)]/[-2sin(π/2+a)+sina]
=(sina-5sina)/(-2cosa+sina)
=-4sina/(-2cosa+sina)
=-4*(-2)cosa/(-2cosa-2cosa)
=8/(-4)
=-2. Put it away
As shown in the figure, in order to study the relationship between the clock and trigonometric function, establish the coordinate system as shown in the figure, and set the position of the second hand tip P (x, y). If the initial position is P0 (32, 12), when the second hand starts to walk normally from P0 & nbsp; (note here t = 0), then the functional relationship between the ordinate y of point P and time t is ()
A. y=sin（π30t+π6）B. y＝sin(−π60t−π6)C. y=sin（-π30t+π6）D. y=sin（-π30t−π3）
From the meaning of the question, the period of the function is t = 60, ω = 2, π 60 = π 30, let the analytic expression of the function be y = sin (- π 30t + φ) (because the second hand moves clockwise) ∵ the initial position is P0 (32,12), when t = 0, y = 12 ∵ sin φ = 12 ∵ φ can take π 6 ∵ the analytic expression of the function is y = sin (- π 30t + π 6), so C is chosen
For the calculation formula of arc length, it is known that the section span is 15 meters long and the section height is 2 meters. 7. For the arc length, please use words to express the calculation formula. I can't remember the meaning of the letters
I don't know the angle. There's only one picture, just like a bow. There's only the length of the bow string and the height of the bow
Arc length L = 2 * a * r
sin(a)=7.5/r
Right triangle: R * r = (r-2.7) * (r-2.7) + 7.5 * 7.5
The radius r = 11.77
Inverse sine: a = 39.58 degrees = 0.6919
Arc length: l = 16.288
To a person to give detailed calculation, formula requirements listed!
Xiao Bo's house needs to install curtains! The unit price of the curtain is 35 yuan per meter! (curtain height is 2.8 meters!) The length of bedroom window is 2 meters, the length of living room window is 5.4 meters! Q: how many square meters of curtains does Xiaobo need? How much is the total price?
Who is the owner of the building?
2 meters for bedroom and 5.4 meters for living room
2 + 5.4 = 7.4M
It is known that the price per meter is 35 yuan
The total price is 7.4x35 = 259 yuan
The total curtain area required is: 7.4x2.8 = 20.72 square meters
A equals 23456b, that is
2.8 * 2 = 5.6, 2.8 * 5.4 = 15.12, so a total of 20.72 square meters of curtains are required, and the total price is 35 * 20.72 = 529.2
Total curtain area = 5.4 × 2 = 10.8 square meters
Total price = 5.4 × 35 = 189 yuan
Why is there no question?
The title is wrong, the unit is not clear. (2 + 5.4) * 35 = 259 yuan, area 7.4 * 2.8 = 20.72 square meters
The total length of the runway in the stadium is 400 meters, in which the ratio of the length of the curve part and the straight part is 2:3, and the curve part is shorter than the straight part ()
A. 66.6%B. 50%C. 33.3%
The length of the curve part is regarded as 2 parts, then the length of the straight part is 3 parts; (3-2) △ 3, = 1 △ 3, ≈ 33.3%; answer: the curve part is 33.3% shorter than the straight part
A mathematical problem, write the process and formula
1+2+3+4+.+1997+1998+1999=?
1+2+3+4+.+1997+1998+1999=(1+1999)*1999/2=1999000
Summation formula of arithmetic sequence: (first term + last term) × number of terms / 2
(first number + last number) x number / 2 = (1 + 1999) x1999 / 2 = 1999000
(0+1999)*2000/2=1999000
1+2+3+4+......+1997+1998+1999
= (1998/2)*(1+1998) + 1999
= 999*1999 + 1999
= 1999000
(a1+an) * n /2
Namely
(1 + 1999) * 1999 /2 = 1999000
1+1999=2000
1999-1=1998
1998 divided by 2 = 999
999 times 2000 = 1998000, plus the number in the middle of 1999.
How to calculate the length of waist tendon? What's the formula?
=The clear span length of the beam is + 15d * 2, and the anchorage / lap length at both ends is 15d, as shown in the lower right corner of 03g101 p24
1、 A product sold 100 tons last year and 95 tons this year. How many percentage points lower than last year?
2、 The sales volume of a certain product is 100 tons this year and 95 tons last year. How many percentage points higher than last year?
(last year's sales - this year's sales) / this year's sales * 100% = growth rate over this year
(last year's sales - this year's sales) / last year's sales * 100% = growth rate over last year
(1)(100-95)/100*100%=5%
(2)(100-95)/95*100%=5.26%
1. (95-100) / 100 = - 5%, down 5 percentage points
2. (100-95) / 95 = 5.26%, up 5.26 percentage points
1 100%-95%=5%
2 100%-95%=5%
1、 A product sold 100 tons last year and 95 tons this year. How many percentage points lower than last year?
(100-95)/100 *100%
2、 The sales volume of a certain product is 100 tons this year and 95 tons last year. How many percentage points higher than last year?
(100-95)/95 *100%
1. (95-100) / 100 = - 5%, down 5 percentage points
2. (100-95) / 95 = 5.26%, up 5.26 percentage points
support
(last year's sales - this year's sales) / this year's sales * 100% = growth rate over this year
(last year's sales - this year's sales) / last year's sales * 100% = growth rate over last year
Calculation formula of arc length
If we know the radius, chord length and chord height, how to calculate the degree of circle center angle?
Example: chord length 1800, chord height 680, radius 935, arc length, arc area
Let the center angle of the circle be α, then according to the known condition: sin α = 900 / 935 = 0.9626
Looking up the sine and cosine table, we can see that α is the degree of the central angle of the circle
Arc length = α / 360 ° * 935 * 2 * π
Arc area = α / 360 ° * 935 ^ 2 * π
Please list the formula
4、 There are 10 identical cylindrical columns in the hall of children's palace. The perimeter of the bottom surface of each column is 0.8m and the height is 6.6m. If one square meter of paint is painted, about 650g of paint is used, how many kg of paint is needed to finish painting these columns?
5、 The side view of a cylinder is a square with side length of 31.4cm
(4) side area of cylinder = perimeter of bottom surface × height 0.8 × 6.6 = 5.28 (square meter) ② weight of paint = side area of cylinder × paint consumption per square meter 5.28 × 650 △ 1000 = 3.432 (kg) 5) radius of cylinder: ∵ perimeter of bottom surface of cylinder 2 π R = 31.4 ∥ r = 31.4 / (2 π) = 5 ② side area s side = square