Proving 139/159 is Not an Upper Bound for E = {(14n + 11)/(16n + 19): n ε N}

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In summary, in order to prove that 139/159 is not an upper bound for the set of real numbers (E), we can set (14n + 11)/(16n + 19) equal to 139/159 and solve for n. By doing so, we can find an integer n that makes the fraction greater than 139/159, therefore proving that 139/159 is not an upper bound for E. It is not necessary to find the "best" or "nearest" n, as any integer n that makes the fraction greater than 139/159 is sufficient.
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teme92
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Homework Statement



Prove that 139/159 is not an upper bound for the set of real numbers:

E ={(14n + 11)/(16n + 19): n ε N}


Homework Equations





The Attempt at a Solution



Right so I let 14n + 11 = 139 and I got n=9.14. Since n is supposed to be natural and the answer I got for n isn't, can I deduce that 139/159 is not an upper bound for E?
 
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You have to find a positive integer such that if you plug it into (14n + 11)/(16n + 19) you get a number greater than 139/159.

 
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Hey shortydeb thanks for the quick reply.

That is what I originally thought but do I not need to get a number n that lies before and after 139/159 but not exactly on it? Its very tedious work if that is the case :/
 
  • #4
Set (14n + 11)/(16n + 19) equal to 139/159 and see what you get for n.
 
  • #5
teme92 said:
Hey shortydeb thanks for the quick reply.

That is what I originally thought but do I not need to get a number n that lies before and after 139/159 but not exactly on it? Its very tedious work if that is the case :/

No. All you need do is find an integer n giving the fraction > 139/159. You do not need to find the "best" or "nearest" n, or anything like that.
 
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Ok I get it now so. Thanks for the help much appreciated
 

FAQ: Proving 139/159 is Not an Upper Bound for E = {(14n + 11)/(16n + 19): n ε N}

1. What is an ordered field?

An ordered field is a mathematical structure consisting of a set of elements, along with two operations (usually addition and multiplication) and a relation called "less than" that satisfies certain axioms. These axioms ensure that the elements of the field can be arranged in a linear order, and that the operations follow the usual rules of arithmetic.

2. How is an ordered field different from a regular field?

While a regular field has operations of addition and multiplication, an ordered field also has a relation called "less than" that allows for the elements to be arranged in a linear order. This means that in an ordered field, there is a concept of numbers being greater or less than each other, whereas in a regular field, all elements are considered equal.

3. What are some examples of ordered fields?

Some examples of ordered fields include the real numbers, the rational numbers, and the complex numbers. These fields all have a linear order defined by the "less than" relation and follow the axioms for an ordered field.

4. How are ordered fields used in scientific research?

Ordered fields are used in many areas of scientific research, particularly in fields such as physics, chemistry, and economics. They provide a framework for understanding and analyzing data and making predictions based on the relationships between different elements.

5. Can an ordered field have elements that are not numbers?

No, an ordered field must have elements that can be represented as numbers. This is because the axioms for an ordered field require the elements to have certain properties that can only be satisfied by numbers. However, these numbers can represent a wide range of quantities, including physical measurements, probabilities, and more.

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