a Given rational numbers a and b find two other rational num
(a) Given rational numbers a and b, find two other rational numbers x and y such that a^2 + b^2 = x^2 + y^2. [Hint: Choose any two integers c and d for which c^2 + d^2 is a square; now write (a^2 + b^2 )(c^2 + d^2) as a sum of Iwo squares.] Illustrate part (a) by expressing 61 = 5^2 + 6^2 as the sum of squares of two rational numbers.
Solution
choose any two integers c,d such that
c2 +d2 =k2 ,k is a rational number
now (a2 +b2)(c2 +d2)=k2 *a2 +k2 *b2 =(ka)2+(kb)2
b)61=25+36=k2 *((5/k)2+(6/k)2) where k is a rational number
