To solve a quadratic equation with one variable by formula, we must first turn it into a general formula.
Then, adjust the coefficient to make it the simplest ratio.
Determine the parameter abc and calculate the discriminant of the equation.
If there are any real roots, the ratio of discriminant value to zero will be known.
There is a real root setting formula, but there is no real root to talk about.
The way to judge an unary quadratic equation is to judge whether an equation is an unary quadratic equation, first of all, to see if it is an integral equation. If so, tidy it up again. If it can be arranged in the form of (a≠0), then this equation is a quadratic equation.
Dial:
① "a ≠ 0" is an important part of the general formula of a quadratic equation. When a=0 and b≠0, it becomes a quadratic equation. On the other hand, if it is clear
It is an unary quadratic equation, which implies the condition of a≠0;
(2) Any univariate quadratic equation can be transformed into a general form after sorting. When judging whether an equation is an unary quadratic equation, it should be transformed into a general form before judging;
(3) Quadratic coefficient, linear coefficient and constant term are all defined in general form, so when determining the coefficient of quadratic equation with one variable, the equation should be transformed into general form first;
The coefficient of item 4 includes the previous symbol. For example, the linear coefficient of x2+5x+3=0 is 5 instead of 5x; The constant term of 3x2+4x- 1=0 is-1 instead of1;
⑤ If the univariate quadratic equation is transformed into the general form of univariate quadratic equation, the quadratic term coefficient, the linear term coefficient and the constant term are pointed out.
The vertex is on the circle, and the angle at which both sides intersect the circle is called the circumferential angle.
The vertex of the fillet is on the circle, and its two sides are the two chords of the circle.
Indirect collocation method for solving quadratic equation with one variable
The known unknowns are separated first, and then factorized.
The adjustment coefficient is reciprocal, and the sum-difference product sets the identity.
Complete square constant, indirect formula is superior.
Similar triangles's so-called similar triangles is the same shape, but different sizes. But as long as the shape is the same, no matter how the size changes, it is similar, so it is called similar triangles.
Two triangles with equal triangles and proportional sides are called similar triangles.
Similar triangles's judgment method is obviously troublesome, because judging whether two triangles are similar by definition needs to consider six elements, namely, whether the three groups of corresponding angles are equal and whether the three groups of corresponding sides are proportional respectively. So we give the following simple methods to judge the similarity of two triangles:
(1) If two sides of a triangle are in direct proportion to two sides of another triangle, and the included angles are equal, then the two triangles are similar;
(2) If three sides of a triangle are proportional to three sides of another triangle, then the two triangles are similar;
(3) If two angles of a triangle are equal to two angles of another triangle, then the two triangles are similar.
The above is the new policy of Guangzhou senior high school entrance examination physical education examination.