How to do math problem 1? To the process.

Solution: (sin -sin ) =sin -2sin sin +sin =3 4

cosα-cosβ)²=cos²α-2cosαcosβ+cos²β=1/4 ②

, 2-2[cos cos + sin sin]=1, i.e., 2-2cos( -=1

cos（α-=1/2

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ob = oa +ab = oa +oa =2*oa ,[square oabc,oa = ab=bc=co].

ob= 2*oa>oa, point b is outside the circle;

co=oa, point c on a circle;

om=ob/2=√2*oa/2

Substitute 2 + 3 into the equation x 2-4x + c = 0

(2+ 3) 2-4(2+ 3)+c=0, then 7+4 3-8-4 3+c=0 c=1, and because x1+x2=-b a=4

So the other root is 4-(2+3)=2-3

The other root is x2, which is obtained by the relationship between the root and the coefficient.

2 + 3) + x2 = 4, so x2 = 2- 3

and (2 + 3) * x2 = c, so c = (2 + 3) (2- 3) = 1

2 + 3 is a root of the equation x 2-4x+c=0, then there is (2+ 3) 2-4*(2+ 3)+c=0 ==>c=1According to Veda's theorem, the sum of two roots = 4

So the other root = 4 - (2 + 3) = 2 - 3

I provide you with ideas, please complete the answer by yourself, you can tell me when the answer is calculated, and I will judge right and wrong for you.

The first question is equivalent to: mx<2x(3)-x(2)-2, from the question, x>0, you may wish to divide x. on both sidesGet.

m<2x(2)-x-2/x.To the right of the equation is f(x).Only the derivative of the value range of mf(x) is easy to solve, and I hope that this part of the landlord can do it himself.

Question 2: It is easy to find out that the axis of symmetry is x=-1, in the definition domain of x, a b is definitely not right, the relationship between the size of x1, x2 and the axis of symmetry is not given, the minimum value of y is the minimum value of the function, please calculate the minimum value of the function by yourself.

If you don't understand, you can ask, and if you are not sure about the answer, you can ask, and I will tell you.

AB squared = BC squared + AC squared.

then ab = under the root number (16 * 16 + 12 * 12) = 20

ab*ad=ad*bc, get ad=ac*bc ab=16*12 20=

ac=a=16, cd=b, cb=c=12, ad=d, db=e, ab=f (all of the following have been replaced by letters).

Because acb=90%, then a +c = f, i.e. 16 + 12 =25 = f, then ab=f=20

Because of cd ab, then adc = adb = 90°, so b +d = a =256 and b +e =c =144

then d -e = (d + e) * (d - e) 256-144 = 112

It is also known that f=d+e=20, then (d+e) = (d+e)*(d+e)=20 = 400

From (d+e) (d-e)=400 112, i.e. 20 (d-e)=400 112, d-e=

d+e=20, d-e=, then d=, e=

b = a -d =, then b =

Answer: ab=20, cd=

square root of ab = (square of 12 + square of 16) = 20

cd=12*16/20=

Solution: Because acb=90°, ac=16, bc=12, according to the Pythagorean theorem, ab 2=ac +bc 2=16 2+12 2=4 2*(16+9)=20 2

So ab=20 (negative values are rounded off).

and s acb=1 2*ac*bc=1 2*16*12=96=1 2*ab*cd=10*cd

So cd=

Because the angle acb = 90 degrees so the Pythagorean theorem ab = under the root number (16*16+12*12)=20

Ad= is solved from the meaning of the question ad 2+cd 2=16*16 and (20-ad) 2+cd 2=12*12

So cd = root number under (16*.)

According to the Pythagorean law: ab=20

1.If you have learned that triangles are similar, then triangle ACD is similar to triangle ABC (A, A, A three angles are equal).

cd/bc=ac/ab，cd=16x12/20=2.If you have not learned that triangles are similar, then let ad=a, db=20-a also according to the Pythagorean law cd 2=(16 -a)=(12 -(20-a) 2).

The solution is a=, cd=

There are so many people upstairs, but none of them have an alternative solution, Coco.

∵cd⊥ab，∠acb=90°

ACD, CDB, and ABC are all right-angled triangles, and according to the Pythagorean theorem, AB = AC +BC = 16 +12 = 400 AB = 20

s abc = 1 2ac bc = 1 2ab cd yields 16 12 = 20 cd

cd=

From the Pythagorean theorem:

ab²=ac²+bc²=16²+12²=400∴ab=20

s abc = 1 2ac bc = 1 2ab cd i.e. 16 12 = 20 cd

cd=

Solution: Because acb = 90 degrees.

So the triangle ACB is a right triangle.

So the S triangle ABC=1 2AC*BC

ab^2=ac^2+bc^2

Because ac=16 bc=12

So the S triangle abc = 96

ab = 20 because cd is vertical ab

So the s triangle abc=1 2ab*cd=96, so cd=

To sum up: ab=20 cd=

When n people, if the first person takes the rate, such as getting his own gun q(n-1)q(n)=1 n+(n-1) n*q(n-1)=1 n+(n-1) n*[1 (n-1)+(n-2) (n-1)q(n-2)]

1/n+1/n+(n-2)/n*q(n-2)**

Solution: According to the Pythagorean theorem:

ab^2=ac^+bc^2=16^2+12^2=4^2*(16+9)=20^2

ab=20;Negative numbers are rounded off.

ac^2-ad^2=bc^2-(ab-ad)^2=bc^2-ab^2-ad^2+2ab*ad

16^2=12^2-20^2+2*20adad=[400+16（16-9）]/40=10+14/5=cd^2=ac^2-ad^2=16^

cd=4√

Use the Pythagorean theorem to find ab.

Ask for cdwith an area formula.

It's unfair, because there is one more of the four numbers that is a multiple of 2 than a multiple of 3, as long as you replace 7 of them with 9, and it doesn't work if you replace it with 6.

cm⊥ab

c=s+t so that a=1, then b=(root number 2) ten 1

c = 2h, so the root number (1-h) ten root number (3 + 2 root number 2-h) = 2h

The definition of the increment function is that when x2 > x1, f(x2) > f(x1), and since 5>4, f(5) > f(4).