Question

The slope of a function at any point (x,y) is e^x/e^x+1.The point (0,2ln2) is on the graph of f.

write the equation of the tangent line to the graph of f at x=0

Answer 1

evaluate the function at given point to get your y value.
Then find derivative of function to get your slope.
Then just plug in your points.

Answer 2

i am unsure
because the function given is slope

Answer 3

not the original, and 0,2 is a random point on f not at the point of tangency

Answer 4

woops, I see what you are saying let me re-read the question now. They gave you the slope of the function...not the function.

Answer 5

i was thinking maybe if i take anti derivative i can get original function?

Answer 6

and then maybe with original equation i can find y and then put into slope intercept?

Answer 7

I'm actually a little confused on it now myself. I'll tell you what I was thinking and maybe it'll make sense to you...

The point (0, 2ln2) is on the graph. so if we use point slope form
y-2ln2=slope
y-2ln2=(e^x)/(e^x +1) .... evaluate with x = 0
y-2ln2 = 1/2(x-0)
y=(x/2) + 2ln2

Answer 8

ya i got slope = 1/2 also

Answer 9

but i think you cant use 2ln2 for equation of the line

Answer 10

0,2ln2 isnt at the point of tangency

Answer 11

although 0 is

Answer 12

It's not at the point of tangency but it is a point on the original f(x). So I would assume you can get the original f(x) from it. When you evaluate f'(x) after getting the original equation you get (1/2).

Answer 13

f'(x) at 0 you get (1/2)

Answer 14

oh i c so it must be right then

Answer 15

* wait 1/2 + 1

Answer 16

y=(x/2) + 2ln2 is the original equation I got. Then when I took the derivative I got
= 1/2+ 2(1/2)
= 1/2 + 1
= 1/2 + 1 = 3/2

Answer 17

From there I guess you would just plug that into point slope form to get the equation of the tangent line.

Answer 18

wait why plug in again if we already got equation of original?

Answer 19

shouldnt that be the answer?

Answer 20

oh wait nvm

Answer 21

got confused but i understnad lol

Answer 22

i c maybe that will work i will try and let you know

Answer 23

cool, let me know. It makes sense to me anyway, but I am not completely sure..... I'm going to break out my graphing calculator soon lol.

Answer 24

off topic ,just realized maywather n cotto fight is today do u have a link?

Answer 25

haha, nah I was actually just about to look for that myself as well.

Answer 26

alright ill let you know if i find one