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On inequality in the first grade of junior high school A, B, C, D four basketball teams compete (main and away), a total of 12 games, each team to carry out six games, winning more than two teams qualified, then, to ensure that qualified, at least to win () games? Please write the process,
1. There are 12 games in total, that is to say, all the winning games are 12, and the 12 winning games are divided into four teams,
2. If you want to qualify, you must get at least the second place
Considering the worst case, if you want to qualify, you have to win more than 4 games, that is, 5 games
So we have to win at least five games
Practice of inequality in grade one of junior high school
1. If the solution set of inequality 3x-a ≥ 4 is x ≥ 1, then a = ()
2. If the solution of the equation 5x = 12 = 4A of X is negative, then the value range of X is ()
The negative integer solution of 3.4x-7 (3x-8) < 4 (25 + x) is ()
4. Given that X and y satisfy the inequality 3x-4 ≥ 2 (x-3) and Y-1 / 6-y + 1 / 3 > 2 respectively, then x y
5. The solution set of inequality 1 / 3 * (1-6x) < - 1 / 2 (4x-7) is ()
(A) All rational numbers (b) all positive numbers (c) all negative numbers (d) have no solution
2. If the solution of the equation 5x + 12 = 4A of X is negative, then the value range of X is ()
1、a=-1
2. There is something wrong with the question
3、-1、-2
4、x>y
5、A
The existence and equality of left and right limits is a necessary and sufficient condition for the existence of limit of function
It is proved that: 1. Necessity: because f (x) exists when x → XO, if a, then the absolute value of F (x) - A
Yes, the existence and equality of left and right limits of a function is a necessary and sufficient condition for the existence of function limits. Both forward and backward inferences are right. There are only left and right limits in a solid, but the limit must be continuous at the point where there is a limit. Inequality can be said to have left and right limits respectively, but it cannot be said that there is a limit at that point
Who can help me to solve a problem? If a matrix satisfies that the square of a minus a plus the identity matrix equals 0, it is proved that a and I-A are invertible, and their inverse matrices are obtained
A² - A + I = 0 -->
A - A² = I -->
A(I-A) = I -->
A, I-A reversible; and:
A^(-1) = I - A
( I - A)^(-1) = A
Plural nouns ending in Y
Change the consonant letter + y into I
Add es to the ending word
When a proper noun ending in Y or a noun ending in vowel + y becomes plural, add s directly to the plural
Is it the pronunciation of the letter before y or the letter itself
The letter itself
Mathematical problems in the pyramid p-abcd, ab ⊥ plane pad, ab ∥ CD, PD = CD
As shown in the figure, in the pyramid p-abcd, ab ⊥ plane pad, ab ∥ CD, PD = ad, e is the midpoint of Pb, f is the point on DC, and DF = 1 / 2Ab, pH is the height of the triangle pad edge. Proof 1) pH ⊥ plane ABCD, 2) if pH = 1, ad = radical 2, FC = 1, find the volume of the pyramid e-bcf, 3) proof: EF ⊥ plane PAB
(1) It is proved that: the pad of ∵ ab ⊥ plane,
∴PH⊥AB,
∵ pH is the height of ad in △ pad,
∴PH⊥AD,
∵AB∩AD=A,
⊥ pH ⊥ plane ABCD
(2) Connect BH, take the midpoint g of BH and connect eg,
∵ e is the midpoint of Pb,
∴EG∥PH,
∵ pH ⊥ plane ABCD,
Ψ eg ⊥ planar ABCD
∵EG=1/2PH=1/2
ψ v = 1 / 3 × s △ BCF × eg = 1 / 3 × 1 / 2 × FC × ad × eg = √ 2 / 12 (root 2 of 12)
(3) Proof: as shown in the figure, take the midpoint m of PA and connect MD and me,
∵ e is the midpoint of Pb,
The me is parallel and equal to 1 / 2Ab
DF is parallel and equal to 1 / 2Ab
The me is parallel and equal to DF
The quadrilateral medf is a parallelogram,
∴EF∥MD,
∵PD=AD,∴MD⊥PA,
⊥ ab ⊥ planar pad, ⊥ MD ⊥ AB,
∩ PA ∩ AB = a, ∩ MD ⊥ plane PAB,
⊥ EF ⊥ plane PAB
∴∥
,
English translation
1. In August
2. On October 20th
3. World record for burping
4. One year and six months
5. Learn to ride a bicycle
7. Movie stars
8. A boy named Tom
In August: in August: on October 20: on October 20: world record for hiccup: a year and six months: learning to ride a bicycle: movie star: a boy named t
If the lengths of two sides of a right triangle are 3 and 4 respectively, the length of the third side should be?
5 or radical 7
would you like coffee or tea
_________ would you like ,coffee _________ tea?
which would you like ,coffee or tea?
What would you like, coffee or tea?
As shown in the figure, M is the midpoint of line AB, AC = 4cm, n is the midpoint of AC, Mn = 3cm, find the length of line cm and ab
Urgent! We must do it well in 10 minutes!
Because AC = 4cm, n is the midpoint of AC
So NC = 2 cm
Because Mn = 3cm, Mn = NC + cm
So cm = Mn_ NC = 3-2 = 1cm
Because m is the midpoint of line ab
So AB = 2am
Am = AC + cm = 4 + 1 = 5cm
AB = 2 * 5 = 10 cm
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