I. Algebraic formula
1, quadratic equation formula -ax? +bx+c=0, where a, b and c are real coefficients, x is unknown, and the value of x can be directly obtained by the root formula, where the discriminant (b? The sign of -4ac) can determine the number of roots of the equation in the real number range.
2. Factorization formula-For some polynomials, the calculation process can be simplified by factorization, such as (a+b)? =a？ +2ab+b？ ; Answer? -B? =(a+b)(a-b)； Answer? -B? =(a-b)(a？ +ab+b？ ) and so on.
3. Newton-Leibniz formula-When calculating the integral value of the function f(x) from a to b, it can be solved by Newton-Leibniz formula: ∫f(x)dx=[f(x)](a to b)+C, where F(x) is the original function of F(x) and c is a constant.
Second, the geometric formula
1, the formulas of trigonometric function-sine theorem, cosine theorem and tangent theorem are important formulas in grade three, which are suitable for solving various triangular problems.
2. Straight line and plane formulas-slope formula, two-point formula and intercept formula are straight line formulas that need to be learned in grade three, while the plane mainly uses several equations such as point method and general formula.
3. Common formulas such as circle area formula, perimeter formula, arc length formula, tangent formula and tangent point formula. They are all geometric formulas of circles that need to be mastered in grade three.
Third, the statistical formula
1, probability formula-classical probability, geometric probability, conditional probability, Bayesian theorem and other probability formulas are the contents that need to be understood in grade three, and are widely used in statistical learning and daily life.
2. Statistical formulas-statistical formulas such as sample mean, sample variance, standard deviation, covariance and correlation coefficient are also statistical knowledge that needs to be mastered in grade three.
3. Generally speaking, the math formula of Grade Three is an indispensable tool in the process of learning math. By strengthening the understanding and application of the formula itself, students' mathematical level can be improved, which will play a great role in their future study and work.