The curve C has equation: (x-y)^2 = 6x +5y -4. Use Implicit differentiation to find dy/dx in terms of x and y. The point B with coordinates (4, 2) lies on C. The normal to C at B meets the x-axis at point A. Find the x-coordinate of A.

We start off by differentiating the equation implicitly which will give us:2(x-y) -2(x-y)dy/dx = 6 + 5dy/dxThen we rearrange to get dy/dx on it's own:dy/dx = (2x-2y-6)/(2x-2y+5)
For the second part of the question we must find the gradient of the tangent at point B, so M = dy/dx at (4,2). Thus M = -2/9. We then find the gradient of the normal which is the negative inverse of M = 9/2. Then we use the equation y-2 = 9/2 *(x-4) but let y=0 since we are finding the x-coordinate of A. Doing this, x must equal 32/9 in order for the equation to be satisfied.

JM
Answered by Jake M. Maths tutor

3727 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

How to find the equation of a tangent to a curve at a specific point.


The curve C has parametric equations x=2cos(t) and y=3cos(2t). Find and expression for dy/dx in terms of t.


Use the quotient rule to differentiate: ln(3x)/(e^4x) with respect to x.


In a triangle ABC, side AB=10 cm, side AC=5cm and the angle BAC=θ, measured in degrees. The area of triangle ABC is 15cm(sq). Find 2 possible values for cosθ and the exact length of BC, given that it is the longest side of the triangle.


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2026 by IXL Learning