Homework Help

Find y' for `e^(xy)=x^2+y-3,` find equation of line tangent to the graph at (2,0)

user profile pic

jmg5639 | Student, Undergraduate | Honors

Posted June 22, 2012 at 3:42 AM via web

dislike 2 like

Find y' for `e^(xy)=x^2+y-3,` find equation of line tangent to the graph at (2,0)

1 Answer | Add Yours

user profile pic

hala718 | High School Teacher | (Level 1) Educator Emeritus

Posted June 22, 2012 at 4:01 AM (Answer #1)

dislike 1 like

`e^(xy) = x^2+y - 3`

We will use explicit differentiation to find y'.

==>` (e^(xy))' = (x^2+y-3)'`

==> `(xy)'e^(xy) = 2x + y'`

==>` (xy'+y)e^(xy) = 2x+y'`

==> `xy'e^(xy) + ye^(xy)= 2x+y'`

Now combine terms with y'.

==> `xy'e^(xy) - y' = 2x - ye^(xy)`

==> `y'(xe^(xy) -1) = 2x -ye^(xy)`

==> `y' = (2x-ye^(xy))/(xe^(xy) -1)`

Now will find the tangent line at the point (2,0)

We will use the equation of the line.

==> y-y1 = m (x-x1)

m is the slope which is the derivative y' at the point (2,0).

==> `y'(2,0) = (2*2-0)/(2e^0 -1) = 4/1 = 4`

Then, the slope is m= 4

==> y-0 = 4(x-2)

==> y= 4x -8 is the equation of the tangent line.

 

Join to answer this question

Join a community of thousands of dedicated teachers and students.

Join eNotes