Which Square Root Of Two Is Irrational?

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The square root of two is irrational. By definition, an irrational number is a number that cannot be expressed as a fraction or ratio. For that reason, irrational numbers, when written as a decimal, will not terminate or continue with a pattern. An indirect proof can be used to justify that radical 2 is irrational. First, assume that is rational. If is rational it can be expressed as a fraction, , where b is not zero and both a and b are whole numbers. Let be in the simplest form such that a and b cannot both be even. If they're even can be further reduced. That means both a and b are odd or one of them is odd and the other is even. = can be rewritten as 2= when both sides of the equation is squared. 2= can then be solved in terms …show more content…

Both answers are also to the correct first five decimal places. What this method is doing is finding a closer approximation to the square root each time we average the numbers and divide. To represent this algebraically, it would be n=a2+e. The variable n represents the square root of the number we are looking for. The variable a is the guess estimate that was made. Finally, e represents the difference of the actual value of the square root of n and a. If we were to start this method with a guess that was too small or too big, it would not matter. When we average the quotient and the new number, we are still getting a closer approximation. So if a was a bigger estimate, then e would be a smaller number. Likewise, if the situation were to be reversed, a and e still have an inverse relationship. So even if the guess is off, the average of the new number and quotient will not be …show more content…

How do we know for certain that the line segment is the exact value of and not a close approximation? We can use the Pythagorean Theorem. The Pythagorean Theorem states a2+b2=c2, or the sum of the legs squared in a right triangle equals the hypotenuse squared (the side opposite the right angle). The legs are both one, this can be expressed as 12+12=c2. It can further be represented as 2=c2. If we square root both sides we get =c. So c must be and not any value. This special concept also creates the properties of a 45 45 90 triangle. In such a triangle, the legs are always equal to each other and thus can be represented by one variable, x. The hypotenuse will always be x . So the ratio of the hypotenuse of this triangle to its legs is :1. This is how can be represented as a line

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