What is the tangent line to the curve y = x^3+4x+5 at the point where x = 2?

First, we must find the value of y when x = 2.

y = x3+4x+5 = (2)3+4(2)+5 = 21

Then we must find the gradient of the tangent line. This can be done by differentiating y with respect to x and substituting x = 2.

dy/dx = 3x2+4 = 3(2)2+4 = 16

Now that we have a point (2,21) and the gradient (m = 16) of our tangent line, we can find the equation of the tangent using the formula:

y-y= m(x-x1)

y-21 = 16(x-2)

y = 16x-32+21

Thus y = 16x-11 is the equation of the tangent

OT
Answered by Oliver T. Maths tutor

13248 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

For the function f(x) = 4x^3 -3x^2 - 6x, find a) All points where df/dx = 0 and b) State if these points are maximum or minimum points.


Find the vertex coordinates of parabola y = 2x^2 - 4x + 1


Given that f(x)= (3+x^2)(x^1/2-7x). Find f'(x) (5marks)


A) Differentiate ln(x) b) integrate ln(x)


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:

© 2025 by IXL Learning