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

12968 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

Solve the simultaneous equation x+y=11(1), x^2+y^2=61 (2)


How do I simply differentiate and what does a differential mean?


Find the integral of xcos(2x) with respect to x


Differentiate y = x^3 + 2x^2 + 4x + 3


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences