Two high school math problems! To detail the process!

It seems that the first question is incomplete.

Question 1: When x < 0, 2 x is large, and both 2 x and 3 x are (0, 1); x=0, equal, and equal to 1; When x > 0, 3 x is larger, and both are greater than 1.

And f(x) decreases at (0,1) and increases at (1,+, so that when x<0, f(3 x) is large; x=0, equal; At x>0, f(3 x) is large.

Question 2: f(x) defines the domain as (0,1), which refers to the domain of unknown numbers, in f(x -3), there is, 0< x -3<1, we get x range of (1,+< p>

①1.When n=2, substituting (x(n+1)) xn=y(xn x(n-1)) gives x3=y

When n=3, substitute (x(n+1)) xn=y(xn x(n-1)) to obtain x4=y 3

When n=4, substituting (x(n+1)) xn=y(xn x(n-1)) gives x5=y 6

Since x1, x3, and x5 are proportional sequences, then y:1=y 6:y, i.e., y 4=1, y=plus or minus 1

2.The general formula for the series xn is: xn=y ((n-1)(n-2) 2), then (x(n+100)) xn=y (100n+4850), a=100, b=4850

It's not hard to figure out the concept. It's annoying to type.,I don't know how to q me.。

Analysis: It can be obtained from a b=max=x-1.

x-1≥0x-1≥(x+1)(x-2)

The simultaneous solution inequality yields 1 x 1 + 2

Analysis: Let x=0, get y=1, exclude c, d

Let x tend to infinity and y tend to 0, excluding a

So choose B.

6.I choose BIt is obtained by a b = max = x-1.

x-1≥0x-1≥(x+1)(x-2)

Simultaneous solution 1 x 1 + 2

7.When bx=0 is selected, y=1 is selected, and c, d are not selected

When x tends to infinity, y tends to 0, and a is not chosen

So choose B.

1，y=(1/4)(x-2)^2-1

2. Piecewise functions

y=x 0<=xy=root[a 2+(x-a) 2] a<=x<2ay=root[a 2+(3a-x) 2] 2a<=x<3ay=4a-x 3a<=x<=a

The image should be a straight line first, then a parabola, and then a straight line, which is about x=2a symmetry

I'll give you a little bit of a dial.

a b≠ empty set:

Think of b = as the abscissa of the intersection of the function x -5x + 6 = 0 from the image and the x-axis.

The two solutions of the function x -5x+6=0 are x=2 x=3, and x=2 x=3 is substituted into x -ax+a -19=0 respectively to solve the empty set of aa c ≠.

Substitute x=2 x=3 into x-ax+a-19=0 respectively to solve a, and take the common value of a twice.