The solution for this problem would be:
slope must be [ - 2 ]...dy/dx = - 4x / y...= - 2 means y = 2x...thus 4 x² + [ 2x]² = 36 or
x = ± 3 √2 / 2 and y = ± 3 √2 ---> d = ± 3 √2 ± 3 √2 = ± 6 √2 ...( 3√2 / 2 , 2√3 ) & ( - 3 √2 / 2 , - 3 √2 ) for negative slopes.
