Question

If x² + y² - 2axy = 0, then `dy/dx` equals ______ 

Options

• `(ay- x)/(y - ax)`

• `(ay - x)/(ay - y)`

• `(x + ay)/(y +ax)`

• `(x + ay)/(ax - y)`

Answer 1

If x² + y² - 2axy = 0, then `dy/dx` equals `underline((ay- x)/(y - ax))`.

Explanation:

x² + y² - 2axy = 0

Differentiating w.r.t. x, we get

`2x + 2y dy/dx - 2a(xdy/dx + y) = 0`

⇒ `2(x - ay) + 2dy/dx(y - ax) = 0`

⇒ `dy/dx = (ay - x)/(y - ax)`