(a)[4]
Prove that $\frac{dy}{dx} = \frac{x + y - 1}{2(x + y) + 1}$.
(b)[3]
Find the coordinates of the point on the curve where the tangent runs parallel to the $x$-axis.
Mathematics 9709 · AS & A Level · Differentiation
Differentiation — practice question
The curve is defined by $\ln(x + y) = x - 2y$.