Use the polynomial identity (x2+y2)2=(x2−y2)2+(2xy)2

to generate a Pythagorean triple when x equals 7 and y equals 4. Write the Pythagorean triple in ascending order.(2 points)
{
,
,
} is a Pythagorean triple.

1 answer

To generate a Pythagorean triple using the polynomial identity \((x^2 + y^2)^2 = (x^2 - y^2)^2 + (2xy)^2\), we start with the values \(x = 7\) and \(y = 4\).

  1. Calculate \(x^2\) and \(y^2\): \[ x^2 = 7^2 = 49 \] \[ y^2 = 4^2 = 16 \]

  2. Now, compute \(x^2 + y^2\): \[ x^2 + y^2 = 49 + 16 = 65 \]

  3. Calculate \((x^2 + y^2)^2\): \[ (x^2 + y^2)^2 = 65^2 = 4225 \]

  4. Now, compute \(x^2 - y^2\) and \(2xy\): \[ x^2 - y^2 = 49 - 16 = 33 \] \[ 2xy = 2 \times 7 \times 4 = 56 \]

  5. Then, compute \((x^2 - y^2)^2\) and \((2xy)^2\): \[ (x^2 - y^2)^2 = 33^2 = 1089 \] \[ (2xy)^2 = 56^2 = 3136 \]

  6. Now we can verify the identity: \[ (x^2 + y^2)^2 = (x^2 - y^2)^2 + (2xy)^2 \] \[ 4225 = 1089 + 3136 \] \[ 4225 = 4225 \quad (\text{True}) \]

  7. The Pythagorean triple is given by \((x^2 - y^2, 2xy, x^2 + y^2)\): \[ (33, 56, 65) \]

Finally, we write the Pythagorean triple in ascending order: \[ {33, 56, 65} \text{ is a Pythagorean triple.} \]