Question

Sketch the curve y=ln(x) and find the tangent line to this curve at the point where the curve crosses the
x-axis.
How do i do this on the computer?

Answer 1

ok... so here is a site that will graph the curve so you can see where it cuts the x-axis

https://www.desmos.com/calculator

next you will need to find the 1st derivative... do you know how to do that..?

Answer 2

no!?

Answer 3

ok... well I don't know how you will find the equation of the tangent.... at that point... if you don't know how to differentiate

Answer 4

at least you're able to identify the point... that has to be part marks

Answer 5

you don't need to know derivatives when you learn logs etc., so if you want to know how to solve just find y=e^x and y=ln(x) is the inverse of it, and as @campbell_st said you can do it in desmos.com

Answer 6

I have no idea what it is, even though I have learned about logs etc :P

Answer 7

well to find a tangent you need a point, which you have and a slope... which you don't have.

By find the 1st derivative... you get the equation of the slope of the tangent.

then you substitute the x value for the point to find the slope of the tangent at the given point...

then you can go and use point slope formula to find the equation of the tangent...

Answer 8

the background info that i was also given was that air pressure decays exponentially at 0.4% per each rise of 30m above sea level. Could i use this information?

Answer 9

thanks @arbershabani97 2 nice curves... how do you find the slope... of the tangent to the log curve...

Answer 10

well I have no clue on the question other what you have posted... the background information doesn't make a lot of sense...

Answer 11

you don't have to
y=e^x
when x=-1 --- y=0.368
when x=0 ---- y=1
when x=1---- y=2.718
when x=2 ---- y=7.389
and you just reflect those points to find y=ln(x) replace x with y
when x=0.368 ---- y=-1
when x=1 ----- y=0
when x=2.718 ---- y=1

Answer 12

you don't have to find slope*

Answer 13

what you have is a refection of the curve

\[y = e^x\]

in the line

y = x

this is what it looks like

Answer 14

but it doesn't help you find the slope of the tangent...

Answer 15

sorry, I don't know how to find the slope

Answer 16

i thought you were asking only for the graph

Answer 17

you need to slope of the tangent to y = ln(x) at (1, 0) to find the equation of the tangent.

Answer 18

perhaps you could just use

http://www.wolframalpha.com/

it will give you a solution with little understanding

Answer 19

could this be right?