To do this requires thinking of the fact that
(A+)² = (A+)(A+) = A² + 2A·( + = A² + 2 + = A² + + 2.
Therefore
A² + + 2 = (A+)²
or
A² + = (A+)² - 2
The theorem which the above proves:
The sum of a square and its reciprocal equals to the square of the
sum of their two square roots decreased by 2
x4 +
That's the sum of a square and its reciprocal, so using the
theorem above it becomes
(x² + )² - 2
What's inside the parentheses is also the sum of a square
and its reciprocal, so using the theorem above it becomes
[(x + )² - 2]² - 2
Now we need to find
by substituting 3 + 2 for x
= = =
= = =
= 3 - 2
Therefore
[(x + )² - 2]² - 2
becomes
[(3 + 2 + 3 - 2)² - 2]² - 2
[(6)² - 2]² - 2
[36 - 2]² - 2
34² - 2
1156 - 2
1154
Edwin