Square root of basic knowledge points of mathematics: ① If the square of a positive number X is equal to A, then this positive number X is called the arithmetic square root of A ... If the square of a number X is equal to A, then this number X is called the square root of A (3) A positive number has two square roots /0 square root is 0/ negative number has no square root. (4) Find the square root of a number, which is called the square root, where a is called the square root. ?
Cubic root: ① If the cube of a number X is equal to A, then this number X is called the cube root of A. ② The cube root of a positive number is positive, the cube root of 0 is 0, and the cube root of a negative number is negative. The operation of finding the cube root of a number is called square root, where a is called square root.
Real numbers: ① Real numbers are divided into rational numbers and irrational numbers. ② In the real number range, the meanings of reciprocal, reciprocal and absolute value are exactly the same as those of reciprocal, reciprocal and absolute value in the rational number range. ③ Every real number can be represented by a point on the number axis.
The key knowledge points of junior high school mathematics are parallel: ① In the same plane, two lines that do not intersect are called parallel lines. ② One and only one straight line is parallel to this straight line after passing through a point outside the straight line. If both lines are parallel to the third line, then the two lines are parallel to each other.
Perpendicular: ① If two lines intersect at right angles, they are perpendicular to each other. (2) The intersection of two mutually perpendicular straight lines is called vertical foot. ③ On the plane, there is one and only one straight line perpendicular to the known straight line at one point.
Perpendicular bisector: A straight line perpendicular to and bisecting a line segment is called perpendicular bisector.
The perpendicular bisector in perpendicular bisector must be a line segment, not a ray or a straight line, which is related to the infinite extension of rays and straight lines. Look at the back, the middle vertical line is a straight line, so when drawing the middle vertical line, be sure to draw two points after the line segment passes through two points (about painting, we will talk about it later).
Perpendicular bisector theorem
Property theorem: the distance between the point on the middle vertical line and the two ends of the line segment is equal;
Decision Theorem: The point with the same distance from the endpoint of line segment 2 is on the middle vertical line of this line segment.
Angular bisector: The ray bisecting an angle is called the angular bisector of the angle.
Basic theorem of mathematics 1. There is only one straight line when two points intersect.
2. The line segment between two points is the shortest.
3. The complementary angles of the same angle or equal angle are equal.
4. The complementary angles of the same angle or equal angle are equal.
5. There is one and only one straight line perpendicular to the known straight line.
6. Of all the line segments connecting a point outside the straight line with points on the straight line, the vertical line segment is the shortest.
7. The parallel axiom passes through a point outside the straight line, and there is only one straight line parallel to this straight line.
8. If two straight lines are parallel to the third straight line, the two straight lines are also parallel to each other.
9. The same angle is equal, and two straight lines are parallel.
10, internal dislocation angles are equal, and two straight lines are parallel.
1 1, the inner angles on the same side are complementary, and the two straight lines are parallel.
12, two straight lines are parallel and have the same angle.
The above are the knowledge points of junior high school mathematics that I summarized for you, for reference only, and I hope it will help you.