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sugar1014
12.07.2019 •
Mathematics
List the members of these sets. a.{x | x is a real number such that x2 = 1} b.{x | x is a positive integer less than 12} c.{x | x is the square of an integer and x < 100} d.{x | x is an integer such that x2 = 2}
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Ответ:
The sets are:
a) {-1, 1}b) {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11}c) {1, 4, 9, 16, 25, 36, 49, 64, 81}d) {∅}.How to find the elements of each set?We need to find all the values of x that meet the given restrictions for each set.
a) Here we know that x is a real number and we must have:
x^2 = 1
Solving for x:
x = ±√1 = ±1
Then this set is:
{-1, 1}
b) Here x is a positive integer smaller than 12, this is just:
{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11}
c) In this case x is a square number, and it must be smaller than 100, so let's find all the square values smaller than 100.
1^2 = 12^2 = 43^2 = 94^2 = 165^2 = 256^2 = 367^2 = 498^2 = 649*9 = 8110*10 = 100 (from this onwards, the squares don't meet the criteria).Then this set is:
{1, 4, 9, 16, 25, 36, 49, 64, 81}
d) Here x must be an integer, such that x^2 = 2
Solving the equation we get:
x = ±√2
But √2 is an irrational number, so there is no integer number that meets this restriction, this means that we have an empty set, this is written as:
{∅}.
If you want to learn more about sets, you can read:
link
Ответ:
x^2 = 1 => x = +/- 1
=> {-1, 1} < answer
b.{x | x is a positive integer less than 12}
1 ≤ x < 12 => {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11} < answer
c.{x | x is the square of an integer and x < 100}
x = n^2 < 100 => n^2 - 100 < 0
=> (n - 10) (n + 10) < 0
=> a) n - 10 > 0 and n + 10 < 0 => n > 10 and n < - 10 which is not possible
b) n - 10 < 0 and n + 10 > 0 => n < 10 and n > - 10 => - 10 < n < 10
=> n = { - 9, - 8, - 7, - 6, - 5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
=> x = {0, 1, 4, 9, 16, 25, 36, 49, 64, 81} < answer
d.{x | x is an integer such that x^2 = 2}
x = {∅ } because x is √2 which is not an interger but an irrational number
=> { ∅ }
Ответ:
If the differences between the group means is large relative to the amount of variability in the scores, the group differences are probably significant. If, however, there is a lot of variability in the scores, then the difference between (or among) the group means will not seem so large, a non-significant difference.
So to summarize, it depends on the group. As there is no shown group, I can't determine what it would be.