Homework Help

Write an equation for the tangent to y=(4x)/(x^2+1) at the point (1,2).

user profile pic

hellome234 | Salutatorian

Posted February 20, 2012 at 2:54 PM via web

dislike 0 like

Write an equation for the tangent to y=(4x)/(x^2+1) at the point (1,2).

Tagged with calculus, math

1 Answer | Add Yours

user profile pic

beckden | High School Teacher | (Level 1) Educator

Posted February 20, 2012 at 3:08 PM (Answer #1)

dislike 0 like

first we have to find the derivative of `y=(4x)/(x^2+1)`

`y'=((x^2+1)(4)-4x(2x))/(x^2+1)^2 = (4x^2+4-8x^2)/(x^2+1)^2=-(4x^2-4)/(x^2+1)^2`

`y'(1)=(4-4)/(1+1)^2=0`

So the slope is 0, so the tangent is a horizontal line.

y=2

Join to answer this question

Join a community of thousands of dedicated teachers and students.

Join eNotes