The complete square formula of junior middle school mathematics formula: (a+b) 2 = A2+2AB+B2 (a-b) 2 = A2-2AB+B2 Square difference formula: (a+b) (a-b) = a 2-b 2 Multiplication and factorial A2. =>-B ≤ A ≤ B | A-B |≥| A |-B |≤ A | Solution of a quadratic equation in one variable-B+√ (B2-4ac)/2A root and coefficient x 1+. 0 Note: The equation has two unequal real roots B2-4ac；; 0 sector area formula s= 1/2*l*r cone volume formula V= 1/3*S*H cone volume formula V= 1/3*pi*r2h oblique prism volume V=S'L note: where s' is the straight cross-sectional area, and l is the one with a long cylinder with a side.