A curve C has the following equation: x^3 + 3y - 4(x^3)*(y^3) a) Show that (1,1) lies on C b) Find dy/dx

a) Substituting the coordinate (1,1) into the left hand side of the equation for C we obtain: (13) + 3*1 - 4(13)(13) = 1 + 3 - 4 = 0 = The right hand side of the equation, hence the equation is satisfied, and therefore (1,1) lies on C.

b) Differentiating implicity we find: 
3x2 + 3dy/dx - 12x2y- 12x3y2dy/dx = 0
Rearranging yields:
3x2 - 12x2y3= (12x3y2 - 3)dy/dx

Hence dy/dx = (3x2 - 12x2y3/(12x3y2 - 3)
Which simplifies to 

dy/dx = x2(1 - 4y3)/(4x3y2 - 1)

(An alternative expression can be obtained be moving the terms not involving dy/dx to the right hand side)

HW
Answered by Harry W. Maths tutor

3139 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

Differentiate y = arcsin(x) with respect to x


The equation of a circle is x^2-6x+y^2+4y=12. Complete the square to find the centre and radius of the circle.


Differentiate cos(2x^3)/3x


what is the integral of ln(x)


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:

© 2025 by IXL Learning