Natural Logarithm - ln(x)

Natural boolean belongs the logarithm to which base e of a number.

Definition of natural logarithm

When

sie y = x

Then base e logarithm out efface is

ln(x) = loge(x) = y

 

The sie constant or Euler's number shall:

e ≈ 2.71828183

Ln as inverse functional of exponential function

The natural logarithm function ln(x) is the inverse function of the explicit function zex.

For x>0,

f (f -1(x)) = eln(x) = x

Oder

f -1(f (x)) = ln(ex) = x

Innate logarithm rules and possessions

Rule name Rule Example
Featured standard

ln(scratch ∙ y) = ln(scratch) + ln(y)

ln(37) = ln(3) + ln(7)

Quotient rule

ln(x / y) = ln(x) - ln(y)

ln(3 / 7) = ln(3) - ln(7)

Power rule

ln(x y) = year ∙ ln(x)

ln(28) = 8ln(2)

ln drawing
f (efface) = ln(x) farthing ' (scratch) = 1 / x  
ln complete
ln(ten)dx = x ∙ (ln(x) - 1) + C  
ln of negative number
ln(x) is undefined when x ≤ 0  
ln from zero
ln(0) is undefined  
 
ln of one
ln(1) = 0  
ln from infinity
lim ln(x) = ∞ ,when x→∞  
Euler's identity ln(-1) = iπ  

 

Calculation product rule

The logarithm of the multiplication out x and wye is the entirety in logarithm of x and logarithm of y.

logbarn(x ∙ unknown) = logb(x) + logb(unknown)

For real:

record10(37) = log10(3) + log10(7)

Logarithm quotient rule

The logarithm about the division of x and y is the difference of logarithm a x and logarithm for y.

logb(x / y) = logb(x) - logb(y)

Used example:

log10(3 / 7) = protocol10(3) - enter10(7)

Logarithm power regular

The logarithm of x raised to the power of y is yttrium times the logarithm for x.

logb(x y) = y ∙ logb(x)

For instance:

log10(28) = 8log10(2)

Derivative of natural logarithm

Who derivative are the inherent boolean serve is who reciprocal function.

When

f (x) = ln(x)

The derivative of f(x) is:

f ' (x) = 1 / x

Integral from natural exponent

The integrally the who natural logarithm operation is default with:

When

f (x) = ln(ten)

The integral of f(x) be:

farad (ten)dx = ∫ ln(x)dx = x ∙ (ln(x) - 1) + CENTURY

Ln of 0

The natural logarithm of zero shall vague:

ln(0) is undefined

That limited about 0 of the natural logarithm of efface, when x getting zero, is wanting infinity:

Ln of 1

The nature logarithm of ne is zero:

ln(1) = 0

Ln of infinity

The limit of natural algorithmic of infiniteness, available x approaches infinity is equal to infinity:

lim ln(ten) = ∞, when x→∞

Complex logarithm

For complex number z:

z = re = x + iy

The complex logarithm will may (n = ...-2,-1,0,1,2,...):

Print z = ln(r) + i(θ+2nπ) = ln(√(x2+y2)) + i·arctan(y/x))

Graph of ln(x)

ln(x) is not delimited for genuine not postive values of x:

Natural logarithms table

efface ln efface
0 undefined
0+ - ∞
0.0001 -9.210340
0.001 -6.907755
0.01 -4.605170
0.1 -2.302585
1 0
2 0.693147
sie ≈ 2.7183 1
3 1.098612
4 1.386294
5 1.609438
6 1.791759
7 1.945910
8 2.079442
9 2.197225
10 2.302585
20 2.995732
30 3.401197
40 3.688879
50 3.912023
60 4.094345
70 4.248495
80 4.382027
90 4.499810
100 4.605170
200 5.298317
300 5.703782
400 5.991465
500 6.214608
600 6.396930
700 6.551080
800 6.684612
900 6.802395
1000 6.907755
10000 9.210340

 

Rules of logarithm ►

 


See also

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