The reciprocal of 9 is 1/9, and the relationship is as follows:

The definition of reciprocal is: if the product of two numbers is 1, one of them is called the reciprocal of the other. For example, a×b= 1, then a and b are reciprocal. According to this definition, we can know that the reciprocal of 9 is 1/9. Because 9× 1/9= 1, 9 and 1/9 are reciprocal.

Related knowledge of reciprocal

1 and reciprocal are mathematical concepts, which represent the quotient of a number sum 1. It has many important applications in mathematics, especially in some advanced mathematics fields. By understanding and studying reciprocal, we can better understand and master mathematical knowledge. Reciprocity definition. The reciprocal refers to the quotient of a number and 1. Mathematically, divide 1 by this number to get its reciprocal.

2. For example, the reciprocal of 5 is 1/5, the reciprocal of 3 is 1/3, and so on. Any non-zero real number has a reciprocal, and 0 has no reciprocal. The product of the reciprocal sum is 1. When the product of two numbers is 1, the two numbers are reciprocal. For example, the product of 2 and 1/2 is 1, so they are reciprocal.

3. Reciprocity and continuous product. If the product of n numbers is 1, then the n numbers are reciprocal. For example, 2×3×4×...×n=n! Then these n numbers are reciprocal. Reciprocal sum factorial. The factorial of positive integers refers to the product of all positive integers less than or equal to this number. For example, the factorial of 5 is 1×2×3×4×5= 120.

4, the relationship between the reciprocal and the original number. The product of the absolute value of the reciprocal of a number and the absolute value of this number is 1. For example, |5|×| 1/5|= 1, |3|×| 1/3|= 1. Special circumstances. 0 has no reciprocal, because any number multiplied by 0 will get 0 instead of 1. Negative numbers have no reciprocal, because negative numbers are multiplied by positive numbers of negative numbers. For example, -2×(- 1/2)= 1 instead of-1.

5. Reciprocal sum equation. The concept of reciprocal can be used to solve some special equations when solving equations. For example, when solving the equation x 2-3x+ 1 = 0, two solutions x = (3 √ 5)/2 can be obtained by finding the root formula, so the concept of reciprocal is needed to solve this equation.