Senior 1 Mathematics. Can you explain the answers to questions 6, 7, 8?

In the interval is a subtraction function, so when x=1 is the maximum value of 3, then (k-2) 1=3 k=5

In the interval is a subtraction function, so from fx2-x we get x>1 and because 2-x>0 so x<2

The time function has a maximum value, so when x = 2 the two functions are equal, the maximum value is 1 (you can draw the images of the two functions separately and find it).

6.Maximum》0, x >0, then k - 2 > 0, the function is a subtraction function, maximum when x = 1. .

7.The function is a subtraction function in the defined domain, then : x > 2 - x , x > 1, and the variable should be in the defined domain, then x > 0 2 - x > 0

8.It is easy to see that f(x) is a decreasing function, g(x) is an increasing function, and when f(x) = g(x), the symbolic formula is the maximum.

The reason is that if f(x0) = g(x0) = t, when x < x0, f(x) > t g(x) x0. f(x)< t, g(x) >t.

Take the small value or < tSo t at this point is the maximum.

The result is a problem of solving the equation, where x = 2 is equal at all times, and the value is 1

<>a intersects the two plane extensions, and then translates the two straight lines on their respective planes to intersect at a point, then the smaller angle is formed.

The range is (0, 2).

The reason why it is not regarded as 0 180° is, in the final analysis, because straight lines do not have the concept of direction, so if they are considered to be 0 180°, then there will be ambiguity on many occasions (for example, one person says that the angle between two straight lines is 45 degrees, and another person says that the angle between two straight lines is 135 degrees, but in fact, two people refer to the same pair of straight lines), which is not conducive to scientific research. In contrast to the Royal Gear Wheel, if you have the concept of a vector, you will find that the angle range of the vector is 0 180°

s（n+1）=2sn+n+5 (1)

sn= 2s(n-1)+n+4 (2)

Subtract formula 1 from formula 2 to get a(n+1)=2an+1

Add 1 to both sides of the equation at the same time, and the deformation is a(n+1)+1=2an+2=2(an+1).

An+1 is a proportional series with 6 as the first term and 2 as the common ratio.

<> the question of collecting dust and renting the state, as long as you draw a picture, the answer will come out.

Later, you can send your own mask to try to solve it.

7. According to the size range of , that is, the relationship between the two, we can know 0< - 2, tan( -=(tan -tan ) (1+tan tan)=2tan (1+tan )=2 [(1 tan )+tan ] 2 =1;

y=α-βarctan(1)=π/4；

8、y=3sin(x+10°+√3sin(20°-x)=3sin(x+10°)+3sin[30°-(x+10°)]

3/2)sin(x+10°)+3/2)cos(x+10°)=√3sin(x+40°)∈3,√3]；