Work out the equation of the tangent to the curve y=x^2+5x-8 at the point (2,6)

Firstly, we know that dy/dx is the gradient of the tangent to a curve. If we know the gradient of the tangent, and the point on the curve where the tangent touches it, we can work out the equation of the tangent.Now, we will find dy/dx. If y=xn, then we know that dy/dx=nxn-1So if y= x2+5x-8, then dy/dx=2x+5.At the point (2,6), where x=2, the gradient of the tangent is dy/dx= 2(2)+5=9. The general equation of a straight line is y=mx+c, where m is the gradient.So, to find the equation of the tangent, we will sub in m=9. So y=9x+c.At the point (2,6), x=2 and y=6, which implies 6=9(2) +c, so c=-12.Therefore, the equation of the tangent is y=9x-12.

AD
Answered by Alexandra D. Further Mathematics tutor

6929 Views

See similar Further Mathematics GCSE tutors

Related Further Mathematics GCSE answers

All answers ▸

Prove that sin(x)^2 - 5cos(x)^2 = 6sin(x)^2 - 5


A circle has equation x^{2}-8x+y^{2}-6y=d. A line is tangent to this circle and passes through points A and B, (0,17) and (17,0) respectively. Find the radius of the circle.


(x+4)((x^2) - kx - 5) is expanded and simplified. The coefficient of the x^2 term twice the coefficient of the x term. Work out the value of k.


The equation of the line L1 is y = 3x – 2 The equation of the line L2 is 3y – 9x + 5 = 0 Show that these two lines are parallel.


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