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).

MS
Answered by Marnie S. Maths tutor

9581 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

Solve 3x - 5 < 16


There are 720 boys in a school and 700 girls. The probability that a girl chosen at random studies french is 3/5 and the probability that a boy chosen at random studies french is 2/3. What is the total number of students in the school that study french?


Expand the expression (3x+2)(3-2x)


Solve algebraically the simultaneous equations: x^2 + y^2 = 25 and y – 3x = 13


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