consider the expression 47/3 + 121 under a square root. will the sun of these numbers produce a rational or irrational number?

1 answer

To determine whether the expression \(\sqrt{\frac{47}{3} + 121}\) produces a rational or irrational number, we will first simplify the expression inside the square root.

  1. First, convert \(121\) into a fraction with a denominator of \(3\): \[ 121 = \frac{121 \times 3}{3} = \frac{363}{3} \]

  2. Next, add \(\frac{47}{3}\) and \(\frac{363}{3}\): \[ \frac{47}{3} + \frac{363}{3} = \frac{47 + 363}{3} = \frac{410}{3} \]

  3. Now, we can write the expression under the square root: \[ \sqrt{\frac{410}{3}} \]

  4. We can further simplify this: \[ \sqrt{\frac{410}{3}} = \frac{\sqrt{410}}{\sqrt{3}} \]

To determine if \(\sqrt{\frac{410}{3}}\) is rational or irrational, we need to investigate \(\sqrt{410}\) and \(\sqrt{3}\):

  • \(\sqrt{3}\) is known to be an irrational number.
  • For \(\sqrt{410}\), we need to check if \(410\) is a perfect square. The prime factorization of \(410\) is: \[ 410 = 2 \times 5 \times 41 \] Since \(410\) does not have any factor raised to an even power, \(\sqrt{410}\) is also an irrational number.

Since the product of two irrational numbers (as long as they are not precisely structured to yield a rational product) will typically result in an irrational number, and given that both \(\sqrt{410}\) and \(\sqrt{3}\) are irrational, we conclude:

\[ \sqrt{\frac{410}{3}} = \frac{\sqrt{410}}{\sqrt{3}} \text{ is also irrational.} \]

Thus, the expression \(\sqrt{\frac{47}{3} + 121}\) produces an irrational number.