On 1/29/20 11:53 AM, harish3679 wrote:

> Hi guys,

>

> To find frequency using semitones value from A=440Hz

>

> We have, f = 2^(n/12)*440 //where n is the semitone value

>

> Now, to find semitone value for A=432Hz from 440Hz

>

> It is 432 = 2^(n/12)*440

>

> I came up with 2^n=0.92668

>

> Although have no clue how to calculate this in octave rather got an error

> saying

>

> "2^(n)=0.92668

> parse error:

>

> invalid left hand side of assignment"

>

> Someone, please shed light on this part

>

>

> Regards,

> Harish

>

You can't write arbitrary equations in Octave and have them figure it

out. The "=" sign is an assignment operation, and you need to have a

single variable on the left hand side. So re-work your equation so that

n is by itself on the left hand side.

I think this means taking the base-2 logarithm of both sides, and ending

up with:

n = log2(0.92688)

And that you can run in Octave:

>> log2(0.92668)

ans = -1.098568597196845e-01

Cheers,

Andrew