# this is a long shot... ln(x) = ?

#### hxc87x

##### Expert Member
here's what i have:
ln(x) = -0.02288669

(x) is supposed to be +- 0.9715

i have no idea how to do the last step, which is to convert that ln thingie to get my (x) which would be my learning curve. i also dont have my text book on me so i cant even check that...

anyone have any idea on how to do this?

#### Pitbull

##### Verboten
here's what i have:
ln(x) = -0.02288669

(x) is supposed to be +- 0.9715

i have no idea how to do the last step, which is to convert that ln thingie to get my (x) which would be my learning curve. i also dont have my text book on me so i cant even check that...

anyone have any idea on how to do this?
Pls post the full question, this is incomplete

#### Drunkard #1

##### Expert Member
I agree, obviously as ln(0.9715) = -0.02891401

#### Devill

##### Damned
isnt e the "reverse" of ln?

IIRC ln(e) = 1

#### EvilDarkElf

##### Well-Known Member
ln(x)=y means e^y=x

is this the equation you're looking for?

#### hxc87x

##### Expert Member
ok...

A worker currently completes 20 units per hour. Took him 75 hours to complete the first 1000 units in a process in which the time of the first unit was halved. Learning curve applies for first 1 000 units.
Calculate the learning curve.

Ln Y = Ln a + (Ln LC/Ln 2) . Ln X

Y(x) = aX^b

Y(x)= cumulative average time per unit
a= time it took to complete first unit
X= range of units completed
b= LOG(learning curve)/LOG2

here's what i've done:

60min/20units = 3min/unit
1st unit = 6min
average = 75x60/1000 = 4.5min/unit

Ln Y = Ln a + (Ln LC/Ln 2) . Ln X
Ln4.5 = Ln6 + (Ln LC/Ln2) x Ln1000

simplified, you get:
Ln LC = -0.0288669

now i just need to finish up...

i think that e thing might be it... will try quick

#### Pitbull

##### Verboten
I fk'ng hate graphs

#### Devill

##### Damned
I fk'ng hate graphs
They are easy and fun.... wait till you should do 3d graphs with very nasty algor.

#### hxc87x

##### Expert Member
yeah, the e thing worked.
e^-0.0288669 = 0.971545699

thanks guys.

#### Devill

##### Damned
Np I found a cool new maths recap site

nvm u came right

#### Drunkard #1

##### Expert Member
Your original post has an extra 2 in it.

##### Expert Member
Still don't know how i passed most of my subjects with equations in.

wtf is "In"

#### hxc87x

##### Expert Member
it's a pain in the ass.
no idea really, has something to do with exponents and logarithms. or something.
also, it's a button on my calculator.

#### Swift-wp

##### Expert Member
log to the base e. also known as natural log.