If the curves x2/a + y2/b = 1 and x2/c + y2/d = 1 intersect at right angles, then which one is the correct relation?
The trick is we verify a – b = c – d by full calculation: use standard identity, substitute, simplify step by step to reach a – b = c – d.
Ref: NCERT Mathematics Class XI — Sets, Relations and Functions
