OpenEuphoria

Re: Tan,Cos and Sin

• Posted by Neil Rigby <NRigbyking at AOL.COM> Oct 08, 1998
• 476 views

>How do I get Tan,Cos or Sin to the power of -1 in Euphoria? I mean that I
>give the function a ratio and it gives me the angle. Arctan seems to give
>tan to the -1 but how do I get the others?

Use of terminology in maths can be confusing, as in this case *Sin to the
power of -1*

The same set of symbols mean different ( but in some sense related ) things
depending on context.

For example
If y is a number:-
y^-1 = the reciprocal of y (the inverse of y)=1/y
if y is a function:-
y^-1 is the inverse FUNCTION of y e.g. the inverse function of x^2 is sqrt(x)
and the inverse FUNCTIONof sin is arcsin
if Y is a matrix:-
Y^-1 is the matrix inverse i.e ( Y^-1 )*( Y ) = I ( the unit matrix )

The symbols ^-1 mean different things in each case but they are similar as:-
for a number (y^-1)(y) = 1 ( the number one )
for a function ( y^-1( y(x) )  = x e.g. sqrt( (x*x) ) = x and arcsin( sin(x) )
= x
for a matrix ( Y^-1 )*( Y ) = I ( the unit matrix )

Hope this is helpful.

Also I agree with John Worthington's comments on *Issue of the week*

>no, No, NO!  ;')  Remember, you have these people like me who really
>enjoy reading these things and learn something.  I just don't have much
>to add in here.  But PLEASE don't drop threads like this.  What seems
>amazing to me is that I am learning, not just Euphoria coding, but about
>programming in general.  Anyways, nothing else to say at the moment, so
>keep up the good work.  ;')

Neil