The routine returns l which is the tangent of point P on circle c with respect to c.

For more details on the result, use detail.

The command with(geometry,tangentpc) allows the use of the abbreviated form of this command.

$\mathrm{with}\left(\mathrm{geometry}\right)\:$

$\mathrm{point}\left(A\,1\,0\right),\mathrm{circle}\left(c\,x^2+y^2=1\,\left[x\,y\right]\right)$

$A,c$

$\mathrm{tangentpc}\left(l\,A\,c\right)$

$l$

$\mathrm{form}\left(l\right)$

$\mathrm{line2d}$

$\mathrm{Equation}\left(l\right)$

$-1+x=0$