A curve has equation y = x^3 - 3x^2 -24x + 5, find the x co-ordinates of the two stationary points of the curve and hence determine whether they are maximum or minimum points.

y = x3 - 3x2 - 24x + 5, First, calculate the derivative of y and find its roots when y = 0:dy/dx = 3x2 - 6x -24 = 0 -> x2 - 2x - 8 = 0 -> (x+2)(x-4) = 0Therefore the coordinates of the stationary points are x = -2, 4. Now calculate the second derivative of y and insert these x values:d2y/dx2 = 6x - 6,For x = -2: d2y/dx2 = -12 - 8 = -18, this result is < 0 so this point is a maximum point.For x = 4, d2y/dx2 = 24 - 6 = 18, this result is > 0 so this point is a minimum point.

TS
Answered by Ted S. Maths tutor

7249 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

When using the trapezium rule to approximate area underneath a curve between 2 limits, what is the effect of increasing the number of strips used?


Find dy/dx of y=e^xcosx


Solve: x^2-7x+6=0


How can you express the complex number z = 2 + 3i in the form z = r(cos x + i sinx)


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