High score! Urgent request for two database curriculum design reports!!! Worry!! Worry!!

I have a database course design report.

1.Draw up the transmission plan.

In order to estimate the total transmission ratio range of the transmission device in order to select the appropriate transmission mechanism and transmission scheme, the rotational speed nw of its drive drum can first be calculated from known conditions, i.e.

v=;d=350mm;

nw=60*1000*V (*d)=60*1000*Generally, the motor with a synchronous speed of 1000R min or 750R min is often used as the prime mover, so the total transmission ratio of the transmission device is about 17 or 25.

2.Select the electric motor.

1) Motor type and structural form.

According to the working requirements and working conditions, the general purpose Y (IP44) series three-phase asynchronous motor is selected. It is a horizontal closed structure.

2) Motor capacity.

1) The output power of the drum shaft is PW

f=2700n;

pw=f*v/1000=2700*

2) Motor output power PD

Solution: Because the domain x < 1 of the function y ln(1 x), then according to the known conditions, a, b are excluded, and then according to the monotonicity, it is obviously a subtractive function, and c is chosen

6 solution: (1) F(0) 0 according to the meaning of the problem, and f(4) 0 = 4(m+5)(m-1) 0

2m+14≥0 ①

16+8(m+3)+2m+14≥0②

m+5)(m-1) ≥0③

Obtained by Synoptic solution m 1

2) F(1) 0 and f(3) 0 =4(m+5)(m-1) 0

1+2(m+3)+2m+14≤ 0①

9+6(m+3)+2m+14≤ 0②

m+5)(m-1) ≥0③

By Synoptic solution m -21 4

Solution 7: When m=0, f(x)=-3x+1

Let f(x)=0, then x=1 3

At this time, the cut-off point of the image on the x-axis is (1, 3, 0), which is in line with the title, when m≠0, let the image pass (x1, 0) (x2, o) then 0 and x1+x2=(3-m) m 0

m-1)(m-9) ≥0①

3-m)/m≥0②

0 m 1 is obtained by Syndicate

In summary, the value range of m is 0 m 1

The positive half axis of the y axis is the positive movement, and the negative half axis represents the reverse direction of the movement, so A is wrong. A varies periodically in the velocity size between 0 and 4s, but it has been moving in a positive direction, and the number is wrong with c.