Can a in all trigonometric functions of the form y = asin (Wx + F) + B be represented by (ymax Ymin) / 2, or is it necessary for y to be symmetric about the X axis?

Can a in all trigonometric functions of the form y = asin (Wx + F) + B be represented by (ymax Ymin) / 2, or is it necessary for y to be symmetric about the X axis?

A is the amplitude, which is the distance from the middle position,
It can be expressed by (ymax - Ymin) / 2, instead of finding the symmetry of Y with respect to the X axis and so on, we can directly reduce the maximum by half of the minimum to get a

The function y = asin (Wx + φ) + B, when x = x1, the minimum value is Ymin; when x = X2, the maximum value is ymax, then a, B and T are

The default is a > = 0, because the standard expression of y = asin (Wx + φ) + B defines a as amplitude > 0, which directly leads to - A + B = ymina + B = ymaxa = (ymax Ymin) / 2B = (ymax + Ymin) / 2. Next, we discuss the period T, because we take the maximum and minimum value of x1-x2 = t / 4 + kt / 2, k = 0,1, - 1,2, - 2 respectively in x1-x2, and get t = (x1-x2) / (1 /

What raw materials can be vulcanized by adding NBR

Sulfur curing system, using sulfur as curing agent, with the corresponding accelerator, such as CZ. Peroxide curing system can also be used
Zinc oxide and stearic acid are active agents for vulcanization. It is not necessary to improve the activity and efficiency of sulfur, but they need to be added in production in order to improve the efficiency. In addition, stearic acid is also a plasticizer, which can be used as mold release agent

Seeking 70 questions of grade 6
Note that you have to pass the equation

Four mixed operations of fraction (1) 1.3 / 7 × 49 / 9 - 4 / 3 2.8 / 9 × 15 / 36 + 1 / 273.12 × 5 / 6 – 2 / 9 × 3 4.8 × 5 / 4 + 1 / 45.6 △ 3 / 8 – 3 / 8 △ 6.4 / 7 × 5 / 9 + 3 / 7 × 5 / 97.5 / 2 - (3 / 2 + 4 / 5) 8.7 / 8 + (1 / 8 + 1 / 9) 9.9 × 5 / 6

What is the melting degree of NBR

Solubility? 150

A 45 kilometer long canal has been excavated for 310 kilometers. How many kilometers more can we just finish 12 kilometers of the canal?

45 × 12 − 310, = 410 − 310, = 110 (km); a: another 110 km, just 12

Suppose that a city will build 1 million square meters of new housing in 2010, of which 250000 square meters are affordable housing. It is estimated that in several years of this year, the area of new housing in the city will increase by 5% on average compared with the previous year, and the area of affordable housing will increase by 100000 square meters every year. According to this plan, the year when the area of affordable housing built in that year exceeds half of that year's new housing area for the first time (already completed) will be calculated (1.052 = 1.1, 1.053 = 1.16, 1.054 = 1.22, 1.055 = 1.28)

2010 is the first year, new housing: 1 million square meters, of which affordable housing: 250000 square meters, the second year, new housing: 100 × 1.05 = 1050000 square meters, of which affordable housing: 25 + 10 = 350000 square meters, the third year, new housing: 100 × 10520000 square meters, of which affordable housing: 25 + 10 × 2 = 450000 square meters In the nth year, new housing: 100 × 1.05n-1 Therefore, when n = 4, the area of new housing = 100 × 1053 = 1.16 million square meters, of which the area of affordable housing = 550000 square meters, less than half when n = 5, the area of new housing = 100 × 1054 = 1.22 million square meters, of which the area of affordable housing = 650000 square meters, more than half So in the fifth year, that is 2014, the area of affordable housing built in that year exceeded half of the new housing area for the first time

1. On the first day of reading a book, Xiao Hua read two seventh of the whole book. If he read another 36 pages, he would read half of the book. How many pages is the book?
2. For a batch of parts, Master Wang processed one eighth the first day and 280 the next. At this time, the ratio of processed parts to unprocessed parts is 3:7. How many parts are there?
3. In class 51, the number of boys accounts for three seventh of the original number of the class. This year, there are two boys. At this time, the number of boys accounts for four ninth of the class. How many people were there in class 51?
Can we not use the solution of the equation

136 △ (1 / 2-2 / 7) = 168 pages 2280 △ [3 / (3 + 7) - 1 / 8] = 1600 3 girls are invariants. In the question "boys account for 3 / 7 of the original number of the class", the number of boys accounts for 3 / 4 of the number of girls. In the question "boys account for 4 / 9 of the class", the number of boys accounts for 5 / 5 of the number of girls

Suppose a city built 1 million square meters of new housing in 2010, of which 250000 square meters are affordable housing. It is estimated that in a few years of this year, the area of new housing in the city will increase by 5% on average compared with the previous year, of which the area of affordable housing will increase by 100000 square meters every year. According to this plan, the year when the area of affordable housing built in that year is more than half of that year's new housing area (1.05 ^ = 1.1, 1.05^3=1.16,1.05^4=1.22,1.05^=1.28）
1/2*100*(1+0.05)^n≤25+10*n
50*1.05^n≤25+10*n
When n = 4, 50 * 1.22 < 25 + 40
The year that the area of affordable housing built in that year exceeded half of that year's new housing area for the first time was 2014
How do you know n = 4? Who can explain it to me?

1/2*100*(1+0.05)^n≤25+10*n
50*1.05^n≤25+10*n
When n = 4, 50 * 1.22 < 25 + 40
The year that the area of affordable housing built in that year exceeded half of that year's new housing area for the first time was 2014
xx

Practical problems of grade 6 in primary school
Use the rope to log the depth. Fold the rope three times to measure the depth. Fold the rope four times to measure the depth. Find the length of the rope

The well depth is x M,
3x+3×4/3=4x+4×1/3
X = 8 / 3M
Rope length = 8 / 3 × 3 + 3 × 4 / 3 = 12m