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sine inverse of something

What is the inverse of the sine function? I've been pulling my hair and
I have no clue nor memory of how to go about solving this little
expression:

sine-1 (read sine inverse) of (1-(x/y))

An answer will be appreciated. Thanks!

Nov 15 '05 #1
9 2596
"Water Cooler v2" <wt*****@yahoo.com> wrote:
What is the inverse of the sine function? I've been pulling my hair and
I have no clue nor memory of how to go about solving this little
expression:

sine-1 (read sine inverse) of (1-(x/y))


To compute the inverse sine aka arcsine in C you should have look at
the asin function; and don't forget to #include <math.h>.

Best regards
--
Irrwahn Grausewitz (ir*******@freenet.de)
welcome to clc : http://www.ungerhu.com/jxh/clc.welcome.txt
clc faq-list : http://www.faqs.org/faqs/C-faq/faq/
clc frequent answers: http://benpfaff.org/writings/clc.
Nov 15 '05 #2
ajm

Water Cooler v2 schrieb:
What is the inverse of the sine function? I've been pulling my hair and
I have no clue nor memory of how to go about solving this little
expression:

sine-1 (read sine inverse) of (1-(x/y))

An answer will be appreciated. Thanks!


as the other post mentioned asin is the appropriate ANSI C function.

but! asin (in math.h) is a function of a single variable (e.g., x) not
two (e.g., x,y) - are you looking to implement a multivariate inverse
sine function (not part of math.h) or just confused ?

hth,
ajm.

Nov 15 '05 #3
i don't think there are multi-variables asin functions
the argument might have an expression involving more than one variable
regards
bharath

Nov 15 '05 #4
ajm
the post was probably meant to be interpreted as composition,i.e.,

f(x,y) = 1 - (x/y)

and the post asked how to compute the composition of sine-1 and f.

Nov 15 '05 #5
"ajm" <a_*******@yahoo.co.uk> writes:
Water Cooler v2 schrieb:
What is the inverse of the sine function? I've been pulling my hair and
I have no clue nor memory of how to go about solving this little
expression:

sine-1 (read sine inverse) of (1-(x/y))

An answer will be appreciated. Thanks!


as the other post mentioned asin is the appropriate ANSI C function.

but! asin (in math.h) is a function of a single variable (e.g., x) not
two (e.g., x,y) - are you looking to implement a multivariate inverse
sine function (not part of math.h) or just confused ?


I think the OP is just looking for asin(1.0 - x/y).

--
Keith Thompson (The_Other_Keith) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.
Nov 15 '05 #6
In article <11**********************@g43g2000cwa.googlegroups .com>,
Water Cooler v2 <wt*****@yahoo.com> wrote:
What is the inverse of the sine function?
-I * log( sqrt(1-x*x) + I * x)

where I is the usual complex root of -1.

I've been pulling my hair and
I have no clue nor memory of how to go about solving this little
expression: sine-1 (read sine inverse) of (1-(x/y))


If you don't have a good symbolic manipulation package (e.g., Maple)
handy, you need to approximate it, such as via a Taylor series...
but then you'd have to Taylor near some particular point, such as

[fixed width font required for below]

maple> taylor(arcsin(x),x=0,9);
3 5 7 9
x + 1/6 x + 3/40 x + 5/112 x + O(x )

maple> subs(x=1-(x/y),%);
3 5 7 9
1 - x/y + 1/6 (1 - x/y) + 3/40 (1 - x/y) + 5/112 (1 - x/y) + O((1 - x/y) )

maple> simplify(%);
3 5 7 9
1 - x/y + 1/6 (1 - x/y) + 3/40 (1 - x/y) + 5/112 (1 - x/y) + O((1 - x/y) )

the error of which would increase as x moved away from 0.
--
Ceci, ce n'est pas une idée.
Nov 15 '05 #7
where did u find that???
bharath

Nov 15 '05 #8
"XXXXXX.working.in.my.blood" <bh********@gmail.com> wrote:
where did u find that???
bharath


Find what? Please preserve some context when replying to a post,
so others might have a fighting chance to find out what you are
talking about.

Best regards
--
Irrwahn Grausewitz (ir*******@freenet.de)
welcome to clc : http://www.ungerhu.com/jxh/clc.welcome.txt
clc faq-list : http://www.faqs.org/faqs/C-faq/faq/
clc frequent answers: http://benpfaff.org/writings/clc.
Nov 15 '05 #9
In article <11**********************@g43g2000cwa.googlegroups .com>,
Apparently in response to my posting:
Water Cooler v2 <wt*****@yahoo.com> wrote:
What is the inverse of the sine function?
-I * log( sqrt(1-x*x) + I * x) where I is the usual complex root of -1.

XXXXXX.working.in.my.blood <bh********@gmail.com> wrote:
where did u find that???

As I hinted in the discussion of the Taylor expansion, I used
the symbolic mathematics package Maple

[fixed width font required for below]

maple> convert(arcsin(x),expln);
2 1/2
-I ln((1 - x ) + I x)
If you do heavy-duty symbolic manipulation, then you should
consider Maple. If you do not need the manipulation engine to be
as strong as possible, but you need a lot of programmability, then
you should consider Mathematica. In either case, other newsgroups
are more appropriate for discussions of their relative properties
(e.g., sci.math.symbolic comp.soft-sys.math.mathematica
comp.soft-sys.math.maple )
--
"This was a Golden Age, a time of high adventure, rich living and
hard dying... but nobody thought so." -- Alfred Bester, TSMD
Nov 15 '05 #10

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