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From: leichter@yale-com.UUCP (Jerry Leichter)
Newsgroups: net.math
Subject: Re: need help
Message-ID: <2844@yale-com.UUCP>
Date: Fri, 3-Feb-84 14:06:39 EST
Article-I.D.: yale-com.2844
Posted: Fri Feb  3 14:06:39 1984
Date-Received: Wed, 8-Feb-84 06:06:59 EST
References: mgweed.6686
Lines: 8

The request was for a way to compute arcsin(x), given sin(x).  This is
actually quite easy.  Given x, you want y = arcsin(x); or, inverting the
equation, you want to solve for y, given sin(y) = x.  A Newton-Raphson
approximation should be quite effective.  Recall that to solve f(y)=x
for y, you will need to be able to compute f and its first derivative.
Since f=sin, you have that; and f'=cos, which you also have since
cos(x)=sin(90-x) (in degrees).
							-- Jerry