There are 180 natural numbers n that have the property that either the number n or the number n+20 is three-digit. This is because there are 180 three-digit numbers from 100 to 999, and for each of these numbers, there is a corresponding natural number n such that either n or n+20 is equal to that three-digit number. Therefore, there are 180 such natural numbers n. **

There are 180 natural numbers that have the property that either the number n or the number n+20 is three digits long. This is because for n to be three digits long, it must be between 100 and 999. So, there are 900 three-digit numbers in total. Since n can be any number between 1 and 999, there are 900 possible values for n. However, we must exclude the numbers from 980 to 999, as n+20 would then exceed 999. This leaves us with 900 - 20 = 880 possible values for n. **

In statistics, an N-sample refers to a sample size of N, where N represents the number of individual observations or data points in the sample. The letter N is often used to denote the size of a sample in statistical analysis. It is important to have a sufficiently large sample size (N) to ensure the reliability and validity of statistical results. A larger sample size generally leads to more accurate and precise estimates of population parameters. **

The set n x n is the Cartesian product of the set of natural numbers with itself, resulting in a set of ordered pairs of natural numbers. For example, if n = 3, then n x n = {(1,1), (1,2), (1,3), (2,1), (2,2), (2,3), (3,1), (3,2), (3,3)}. This can be visualized as a grid with rows and columns of natural numbers. The set n x n x n is the Cartesian product of the set of natural numbers with itself three times, resulting in a set of ordered triples of natural numbers. For example, if n = 2, then n x n x n = {(1,1,1), (1,1,2), (1,2,1), (1,2,2), (2,1,1), (2,1,2), (2,2, **

To show that the mapping n x n -> n^m * 2^n+1 - 1 is a bijection, we need to demonstrate that it is both injective and surjective. To show injectivity, we need to prove that distinct elements in the domain map to distinct elements in the codomain. This can be done by showing that if (a, b) and (c, d) are distinct pairs in n x n, then n^m * 2^a+1 - 1 and n^m * 2^c+1 - 1 are distinct in n^m * 2^n+1 - 1. To show surjectivity, we need to prove that every element in the codomain has a pre-image in the domain. This can be done by showing that for every element in n^m * 2^n+1 - 1, there exists a pair (a, b) in n x n such that **

The limit of n * sqrt(n+71) as n approaches infinity is infinity. This can be seen by considering the behavior of the function as n becomes very large. As n increases, the value of n * sqrt(n+71) also increases without bound, as the square root term dominates the behavior of the function. Therefore, the limit of n * sqrt(n+71) as n approaches infinity is infinity. **

Yes, the sets N and N are of equal power. Both sets represent the set of natural numbers, which includes all positive integers starting from 1. Since both sets have the same elements and there is a one-to-one correspondence between them (each natural number in N corresponds to the same natural number in N), they are considered to have the same cardinality or power. **

A mapping from n to n is equinumerous and countable because it is a one-to-one correspondence between the natural numbers. If n were natural numbers without zero, a mapping from n to n would still be countable because it would still be a one-to-one correspondence between the natural numbers. In both cases, the mapping is countable because it can be put into a one-to-one correspondence with the set of natural numbers. **