If f (x + 1) = x & # 178; - 2x-15, then f (16) =?

If f (x + 1) = x & # 178; - 2x-15, then f (16) =?

f(x+1)=x^2-2x-15
=x^2-2x+1-1-15
=(x-1)^2-16
=(x+1-2)^2-16
f(x)=(x-2)^2-16
f(16)=(16-2)^2-16
=14^2-16
=196-16
=180

Given f (2x) = (1 + X & # 178;) / x, the value of F (2) is

This is a relatively simple topic
Because f (2x) = (1 + X & # 178;) / X
Equivalent deformation: F (2x) = 2 [1 + (1 / 4) 2x & # 178;] / 2x
That is, f (x) = 2 (1 + 1 / 4x & # 178;) / X
f(2)=2

A car moves at a speed of 10 meters per second along the straight road at a constant speed. When it encounters an obstacle, it has to brake immediately. If it decelerates at a speed of 2 meters per second, it moves in a straight line. After 6 seconds, the displacement of the car is () a24m b25m c26m d30m

The formula is s = vt-0.5a (the square of T) = 10 * 6-0.5 * 2 * 36 = 24, so a

If M > 1, am-1 + am + 1-am2 = 0, s2m-1 = 38, then M is equal to ()
A. 38B. 20C. 10D. 9

According to the property of arithmetic sequence, we can get: am-1 + am + 1 = 2am, then am-1 + am + 1-am2 = am (2-AM) = 0, the solution is: am = 0 or am = 2, if am is equal to 0, it is obvious that s2m-1 = (2m − 1) (a1 + A2M − 1) 2 = (2m-1) am = 38 does not hold, so am = 2, s2m-1 = (2m-1) am = 4M-2 = 38, the solution is m = 10

A truck stops at 22.5m after sudden braking. Suppose that the braking process of the truck is uniform deceleration and linear motion, and the acceleration is 5m / S2
A truck stops at 22.5m after sudden braking. Suppose that the braking process of the truck is uniform deceleration and linear motion, and the acceleration is 5m / S2. How fast does it start braking?

Vt=0
a=-5
s=22.5
Vt^2-V0^2=2as
0-V0^2=-2*5*22.5
V0^2=225
V0=15m/s
It starts braking at a speed of 15 m / s

Xiaoming runs 6 meters per second and Xiaogang rides 14 meters per second. They walk in the same direction at the same time. After a few seconds, they meet for the second time
Using equation

400/（14-6）=50

1. A and B run at a constant speed on a 400 meter circular track. If they start at the same place and walk in opposite directions at the same time, they meet every two minutes. If they walk in the same direction, they meet every six minutes. It is known that a runs faster than B. how many laps do a and B run each minute?
2. In order to improve the living environment in the community, the neighborhood committee raises funds to transform the surrounding environment. This project can be completed by team a and team B in 16 days, and team a can complete it in 24 days alone. In actual construction, team a will be transferred after 4 days of cooperation between team a and team B, and the rest will be completed by team B. how long will team B need?

1. Let a be X1 meters per minute and B be x2 meters per minute
Solving (x1 + x2) * 2 = 400 by using a series of equations
(x1-x2)*6=400
2. If the total amount of the project is 1, Party B will complete the project in X days
1 / 24 + 1 / x = 1 / 16, x = 1 / 48, B alone for 48 days, 1 / 48 every day
In actual construction:
Completion in the first four days: (1 / 24 + 1 / 48) * 4 = 1 / 4
The remaining three quarters,
(3/4)/(1/48)=36
It will take another 36 days

There are four points ABCD on the number axis, the distance between them and the origin is 1, 2, 3 and 4 length units respectively, and points a and C are on the left side of the origin, and points B and D are on the right side of the origin
(1) Please write the numbers represented by a, B, C and D respectively;
(2) Compare the four numbers and connect them with ">"

(1) ∵ there are four points ABCD on the number axis, and their distances from the origin are 1, 2, 3 and 4 length units respectively, and points a and C are on the left side of the origin, and points B and D are on the right side of the origin
A, B, C and D denote - 1, 2, - 2 and 4 respectively
（2）4>2>-1>-2

There is a hat with a cylindrical crown and a circular brim. The diameter, height and brim width of the crown are 2 mm,
How many square decimeters of cloth should we use at least?
Speed, now!

Radius of small circle = 1 decimeter
Big circle radius = 4 △ 2 = 2 decimeters
Height = 2 decimeters
Need cloth
=Circle area + circle area + side area
=3.14×1²+3.14×（2²-1²）+3.14×2×2
=25.12 square decimeters

It is known that the first side of a triangle is 3A + 2B, the second side is A-B longer than the first side, and the third side is 2A shorter than the second side