Find the differential of f(x)=y where y=3x^2+2x+4. Hence find the coordinates of the minimum point of f(x)

The differential of f(x) is f'(x)=6x+2 because we apply this basic formula: the differential of kxn = knxn-1 where k is a constant.This is a positive quadratic, so it has a U shape that is above the x-axis (I would draw a sketch of the graph at this point). This means it has only got one point where the gradient is zero. This must be the minimum point of f(x) (I would demonstrate this on the sketch of the graph).Therefore since f'(x) tells us the gradient of f(x), the minimum point will be where f'(x)=0, so we can say 6x+2=0.Solving for this gives x=-1/3. To find the y value for the minimum point we calculate f(-1/3) by substituting x=-1/3 back into the original equation y=3x2+2x+4. This gives a value of 11/3.Hence the minimum point of f(x) is (-1/3, 11/3)

Answered by Maths tutor

3418 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

A uniform ladder of mass 5 kg sits upon a smooth wall and atop a rough floor. The floor and wall are perpendicular. Draw a free body diagram for the ladder (you do not need to calculate any forces).


Relative to a fixed origin O, the point A has position vector (8i+13j-2k), the point B has position vector (10i+14j-4k). A line l passes through points A and B. Find the vector equation of this line.


What is a 'derivative'?


Find the factors of x^3−7x−6


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:

© 2026 by IXL Learning