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#Engineering

IMLN

Excel Functions

Get natural log complex number

Syntax

EXCEL
=IMLN(complex_num)

Arguments

Parameter Description
complex_num The complex number in the form "x+yi".

Return Value

Returns the logarithm of the complex number.

Details

The Excel IMLN function returns the natural logarithm of a complex number. For example, given the complex number "3+4i" as input, the function returns the logarithm of the complex number. The real part of the output is equal to the natural logarithm of the distance from the origin to the point "3+4i" in the complex plane. The imaginary part of the output is equal to the angle in radians of the complex number relative to the positive real axis. Given a complex number z, the complex logarithm is defined as: In Excel, the complex logarithm is equal to the following formula where cell B6 contains a complex number:

Examples

Example 1

The Excel IMLN function returns the natural logarithm of a complex number. For example, given the complex number "3+4i" as input, the function returns

EXCEL
=IMLN(COMPLEX(3,4)) // returns 1.6094379124341 + 0.927295218001612i
Example 2

The real part of the output is equal to the natural logarithm of the distance from the origin to the point "3+4i" in the complex plane.

EXCEL
=LN(IMABS(COMPLEX(3,4))) // returns 1.609437912
Example 3

The imaginary part of the output is equal to the angle in radians of the complex number relative to the positive real axis.

EXCEL
=IMARGUMENT(COMPLEX(3,4)) // returns 0.927295218
Explanation

In Excel, the complex logarithm is equal to the following formula where cell B6 contains a complex number:

EXCEL
=COMPLEX(LN(IMABS(B6)),IMARGUMENT(B6))
Visualizing the Output

Geometrically, the real part of the function's output equals the natural logarithm of the distance from the origin to the point in the complex plane.

EXCEL
=IMREAL(IMLN(COMPLEX(3,4))) // returns 1.609437912434100
Visualizing the Output

Geometrically, the imaginary part equals the angle in radians of the complex number output by the function.

EXCEL
=IMAGINARY(IMLN(COMPLEX(3,4))) // returns 0.927295218

See Also

COMPLEX LN IMABS IMARGUMENT