Find the co ordinates and nature of the turning points of the curve C withe equation, y=2x^3-5x^2-4x+2

Firstly, Differentiate the equation to find dy/dx. (dy/dx = 6x^2-10x-4)dy/dx shows the rate of change of the curve at a point, so at the stationary point dy/dx =0. So, put dy/dx = 0 and solve using factorisation. 6x^2 -10x -4=0,(x-2)(6x+2)=0x=2 or x=-1/3To find the y co ordinate plug these x values into the equation of the curve. y=2x2^3-5x2^2-4x2+2=-10y=2x(-1/3)^3-5x(-1/3)^2-4x(-1/3)+2=2.70The nature of the turning point is found using the double derrivative. So differentiate dy/dx to find d^2y/dx^2.d^2y/dx^2=12x-10where x =2:d^2y/dx^2=12x2-10=14If d^2y/dx^2>0 the point is a minimum. So, where x =2 the stationary point is a minimum.where x =-1/3:d^2y/dx^2=12x(-1/3)-10=-14If d^2y/dx^2<0 the point is a maximum. So, where x =-1/3 the stationary point is a maximum.

AK
Answered by Asha K. Maths tutor

9146 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

f(x) is defined by f(x) = 3*x^3 + 2*x^2 - 7*x + 2. Find f(1).


The curve C has a equation y=(2x-3)^5; point P (0.5,-32)lies on that curve. Work out the equation to the tangent to C at point P in the form of y=mx+c


Solve the simultaneous equations y + 4x + 1 = 0 and y^2 + 5x^2 + 2x = 0


What is a parametric equation?


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