The equation of a curve is y = (x + 3)^2 + 5. Find the coordinates of the turning point.

We are asked to find the coordinates of the turning point of a line, and we should first remind ourselves of what this means. A turning point on a line is either a maximum or minimum point, or a point of inflection. (These may be easily represented on a graph). They are all points of zero gradient. When we are given the equation of a line and are asked to find an equation for the gradient, what do we do? We differentiate it!
So if y = (x + 3)^2 + 5, then dy/dx = 2 x (x + 3). (Here we used basic differentiation rules which can be revised if the student requires).
Because we are finding the points with zero gradient, we must put dy/dx = 0 which implies that 2 x (x + 3) = 0, which in turn implies that x = -3.
So we know our x-coordinate, but we must substitute this in to our equation of a line so that we can find the y-coordinate. y = (x + 3)^2 + 5, so at our turning point y = ((-3) + 3)^2 +5 which implies that y = 5.
So we have found that x = -3 and y = 5, and therefore the coordinates of the turning point are (-3, 5).

Answered by Marnie S. Maths tutor

8797 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

Solve the equation (3x**2 + 8x + 4) = 0


ABC is an isosceles triangle such that AB = AC A has coordinates (4, 37) B and C lie on the line with equation 3y = 2x + 12 Find an equation of the line of symmetry of triangle ABC. Give your answer in the form px + qy = r where p, q and are integers (5


Bill buys 8 identical cricket balls. The total cost is £169.04 Work out the total cost of 19 of these cricket balls. (Calculator allowed).


Factorise x²+5x+6.


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 2013–2024

Terms & Conditions|Privacy Policy
Cookie Preferences