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Judge the truth of the negation of proposition p: the square of (- 2) under the root sign = 2 Judge the truth of the negation of proposition p: the square of (- 2) under the root = - 2 The title was copied wrong just now sorry
The square of (- 2) under the root = - 2 is a false proposition
So the negation of the square of (- 2) under the root sign = - 2 is a true proposition
Judge whether the following proposition is true or false. If it is true, please write the proof process. If it is false, please give a counter example
1. It is known that a, B and C are real numbers. If AC = BC, then a = B
2. The complement of an angle must be obtuse
The first false proposition, when C = 0, AC = BC, then a may not be equal to B
The second false, when the angle is obtuse, its complement is acute
If the following two propositions are true or false, please give counter examples. If they are true, please give proof
Proposition 1: "a triangle whose bisector of a triangle's corner is the center line on the opposite side is an isosceles triangle."
Proposition 2: "there are two congruent triangles with two sides and the height of one side corresponding to the same."
The true proposition is as follows: D is the midpoint of BC, ad bisection angle BAC extends ad, to point E, makes ad = De, connects CE, because ad = De, BD = CD, angle ADB = angle CDE (opposite vertex angle), so triangle abd and triangle ECD are congruent (opposite corner edge) so AB = CE, angle bad = angle CED, because ad bisection angle BAC, so angle bad = angle CAD, so angle CAD = angle CED, so AC = CE, so AC = AB, so triangle ABC is isosceles triangle; The right triangle abd and the right triangle abd are the right triangle abd and the right triangle abd and the right triangle abd and the right triangle abd and the right triangle abd are the right triangle abd and the right triangle abd and the right triangle abd and the right triangle abd and the right triangle abd and the right triangle abd and the right triangle abd and the right triangle abd are the right triangle abd and the right triangle abd and the right triangle abd and the right triangle abd; B \\\# 39; D \\\3535; the middle AB = A and ab = a \\\\\\\\\\\\\\\; C & # 39; is SAS, ABC and a & # 39; B & # 39; C & # 39; congruent
Simplify the square of (a-b) + the square of (A-C) + the square of (B-C)
（a-b）^2+(a-c)^2+(b-c)^2=a^2-2ab+b^2+a^2-2ac+c^2+b^2-2bc+c^2=2(a^2+b^2+c^2-ab-ac-bc)
Li Wei rides a motorcycle from his home to the railway station. If he travels 30 kilometers per hour, he will start 15 minutes earlier than the train. If he travels 18 kilometers per hour, he will leave 5 minutes later than the train. If Li Wei plans to arrive at the railway station 10 minutes before the train leaves, what is the speed of Li Wei's motorcycle at this time?
Boy, let's do our homework
Compare the size of √ 2014 - √ 2013, √ 2012 - √ 2011, explain the reason and ask for help
Comparison of the size of √ 2014 + √ 2013 and √ 2012 + √ 2011
There is a mountain road. When a car goes up the mountain, it travels 30 kilometers per hour. When it returns from the original road, it travels 50 kilometers per hour. How about the average speed of the car when it goes up and down the mountain?
It's before 9:00 tonight!
Average speed of car up and down hill: (1 + 1) / (1 / 30 + 1 / 50) = 37.5 (km / h)
If at least one of the three parabola y = x ^ 2 + 4ax-4a + 3, y = x ^ 2 + (A-1) x + A ^ 2, y = x ^ 2 + 2ax-2a has a common point with X axis, the value range of a is obtained
RT
The opposite of the problem: if three parabola y = x ^ 2 + 4ax-4a + 3, y = x ^ 2 + (A-1) x + A ^ 2, y = x ^ 2 + 2ax-2a have no common point with X axis,
Then the discriminant is less than 0, (4a) ^ 2-4 (3-4A)
How many liters of gasoline does a car use when driving 2 / 3 km? How many kilometers can a car drive when driving 1 km?
① 3 / 25 ／ 3 / 2
=3 / 25 × 2 / 3
=2 / 25 (L)
The range of (sin α - cos α) / (sin α + cos α)
(sinα-cosα)/(sinα+cosα)
=（tanα-1)/(tanα+1)
=(tanα-tanπ/4)/(1+tanαtanπ/4)
=tan(α-π/4)
Range (- ∞, + ∞)
RELATED INFORMATIONS
- 1. To judge a proposition, if a > 0, then the bisection of a > the true or false of A. if it is a true proposition, please prove it. If it is a false proposition, please give a counter example
- 2. Judge whether the following propositions are true or false. If they are true, please give proof. If they are false, please give counter examples 1. If the two sides of a corner are parallel to the two sides of the other corner, then the two corners are equal 2. Two triangles of equal area are congruent triangles 3. The sum of the distances from any point in the equilateral triangle to the three sides of the triangle is equal to the height of the equilateral triangle 4. There are two congruent triangles with equal heights on both sides and one of them 5. There are two congruent triangles whose heights on the two sides and the third side correspond to the same
- 3. The counter example is used to show that the proposition "if M > 1, then x ^ 2-2x + M = 0 has real root" is a false proposition
- 4. Give counter examples to prove that the following propositions are false propositions (1) if a > b, then 1 / A
- 5. Judge whether the following propositions are true or false? If false, give counter examples; if true, give proof (1) An angle must be less than its complement (2) If two lines are parallel, the inner angles of the same side must not be equal
- 6. If AB = 0, then a = 0 is a false proposition
- 7. A counterexample is given to show that the following proposition is a false proposition, [1] if a > b, then 1 / A
- 8. Please give a counter example to show that the following proposition is false 1. Equal angles are right angles 2, if a + B = 0, then a = 0, B = 0 3. If ∠ 1 is greater than ∠ 2, then ∠ 1 is an obtuse angle
- 9. If the real number a B satisfies a + B < 4, then a = 1 and B = 2 find its inverse proposition, no proposition, inverse no proposition, and its true and false
- 10. Write a proposition that the sum of two rational numbers is the inverse proposition of rational numbers. If the inverse proposition is not sure of the answer, don't mistake people!
- 11. Given the condition P: | x + 1 | > 2 and the condition Q: 5x-6 is greater than the square of X, what is the condition of its no proposition
- 12. It is known that: P = a square + 3AB + b square, q = a square-3ab + b square, and P - [q-2p - (- P-Q)] + r = a square + 2Ab + b square
- 13. Given proposition p: x > 0, proposition q: x square > 0, then p is a, B and C of Q, and a + b > C is a, B and V Given the proposition p: x > 0 and the proposition q: x square > 0, then p is Q a. If B and C are three line segments, then a + b > C is that a, B and V can form a triangle Li Min is an 18-year-old college student
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- 15. If the rational numbers a and B satisfy | ab-2 | + | 1-B | = 0, Let's try to find one of ab ＋ (a ＋ 1) (B ＋ 1) ＋ (a ＋ 2) (B ＋ 2) ＋ ＋﹙a＋2011）﹙b＋2011 A value of 1 / 2
- 16. Mathematical problems know that a and B are rational numbers, a > 0, B < 0. Simplify | B | - | a | + | A-B | + | a + B| It is known that a and B are rational numbers, a > 0, B < 0. Simplify | B | - | a | + | A-B | + | a + B|
- 17. If a and B are rational numbers and | a | + | B | = 0, then () A. A and B are opposite numbers, B. A = b = 0C. A and B have opposite signs, and the value of d. A and B does not exist
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- 19. If a and B satisfy a + B = 3 and A-B = 2, then A-B = ()
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