Maths - Square Root

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Simon Knight
Posts: 389
Joined: Wed Nov 04, 2009 11:41 am
Location: Gunthorpe, North Lincs, UK

Maths - Square Root

Hi,
I'm just trying to write my first library widget using LCB and need to calculate the square root of several numbers. I can find no direct command so should I be using raise to the power or have I missed something?

best wishes

Simon
best wishes
Skids

[-hh]
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Location: Göttingen, DE

Re: Maths - Square Root

There is no "sqrt(x)" in LCB. Instead use

x^0.5 or exp(0.5*ln(x)) for 0<=x.

[The case a=0 is included in the definition of a^b := exp(b*ln(a)).]
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Simon Knight
Posts: 389
Joined: Wed Nov 04, 2009 11:41 am
Location: Gunthorpe, North Lincs, UK

Re: Maths - Square Root

[The case a=0 is included in the definition of a^b := exp(b*ln(a)).]
I'll take your word on that!

Thanks.
best wishes
Skids

Thierry
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Re: Maths - Square Root

Simon Knight wrote: I'll take your word on that!
You can

[-hh] has a serious computer and maths background!

Regards,

Thierry
Thierry Douez - https://sunny-tdz.com
Pourquoi tant de notes lorsqu'il suffit de jouer les plus belles... [Barbara]

Simon Knight
Posts: 389
Joined: Wed Nov 04, 2009 11:41 am
Location: Gunthorpe, North Lincs, UK

Re: Maths - Square Root

My school boy maths just does not cut it.
best wishes
Skids

[-hh]
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Posts: 1682
Joined: Thu Feb 28, 2013 11:52 pm
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Re: Maths - Square Root

The case a=0 is included in the definition of a^b := exp(b*ln(a)).
To make it simple I meant with that LC computes as needed: exp(0.5*ln(0))=0
[what is the limit of exp(0.5*ln(x)) for 0 < x -> 0]

The equality (extended by the limit above for x=0)
sqrt(x)=exp(0.5*ln(x)) if 0<=x
is very important for the case that the "^" key on a keyboard becomes ever defunct by frequent GPS computings
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LCMark
Livecode Staff Member
Posts: 973
Joined: Thu Apr 11, 2013 11:27 am

Re: Maths - Square Root

This has been added to 'develop' now: http://quality.livecode.com/show_bug.cgi?id=20079

It will be in DP9.