A curve has an equation of y = 20x - x^2 - 2x^3, with one stationary point at P=-2. Find the other stationary point, find the d^2y/dx^2 to determine if point P is a maximum or minium.

We know that a stationary point is found when the gradient of the curve is equal to zero, this is found by equaling the derivative (dy/dx) equal to zero. Differentiating the expression will find a quadratic that can be factorised into two brackets, the two brackets represent the two co-ordinates of the two stationary points, one of which will be P=-2 and the other is found to be x=5/3.The second derivative of the expression can be found, and when P is substituted in, a value is found which represents if it is a maximum or minimum value of the curve. This is found to be d2y/dx2 = 22, which is a positive value and therefore a minimum curve point.

Answered by Georgia S. Maths tutor

2756 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

The point P lies on a curve with equation: x=(4y-sin2y)^2. (i) Given P has coordinates (x, pi/2) find x. (ii) The tangent to the curve at P cuts the y-axis at the point A. Use calculus to find the coordinates of the point A.


Integrate e^(2x)


A curve has an equation: (2x^2)*y +2x + 4y – cos(pi*y) = 17. Find dy/dx


Express 3sin(2x) + 5cos(2x) in the form Rsin(2x+a), R>0 0<a<pi/2


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences