A curve has the equation x2−xy+y2=12x^2 - xy + y^2 = 12x2−xy+y2=12
The gradient of the tangent to the curve is 1 at the points P P\,P and QQQ.
Show that x+y=0x + y = 0x+y=0 at P P\,P and QQQ.
Find the coordinates of P P\,P and QQQ.
47 exam-style questions on Edexcel A Level Maths 9.8 Implicit Differentiation. Each one has a worked solution and a mark scheme showing where the marks go.