# [R] isolating X on an expression

Gabor Grothendieck ggrothendieck at gmail.com
Wed Sep 10 15:59:19 CEST 2008

```Try Ryacas:

> library(Ryacas)
> A <- Sym("A"); B <- Sym("B"); X <- Sym("X"); Y <- Sym("Y"); K <- Sym("K")
> Solve(K==(sin(A) * sin(B) )  + ( cos(A) * cos(B) * cos ( X - Y ) ), "X")
[1] "Starting Yacas!"
expression(list(X == Y + acos((K - sin(A) * sin(B))/(cos(A) *
cos(B))), X == Y - acos((K - sin(A) * sin(B))/(cos(A) * cos(B)))))

On Wed, Sep 10, 2008 at 9:09 AM, milton ruser <milton.ruser at gmail.com> wrote:
> Dear R-gurus,
> I know that it is not a R problem, but as need
> to implement some solution for this on R, I would
> like to know if someone help me on how to isolate
> X on the expression below.
>
> K=(sen A * sen B )  + ( cos A * cos B * cos ( X - Y ) )
>
> Any help are welcome
>
> mitinho astronauta
> brazil
>
>        [[alternative HTML version deleted]]
>
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>

```