$1-{2\over{\pi-1}}$ is algebraic implies that ${1\over{\pi-1}}=a$ where $a$ is algebraic, this implies that $\pi-1=1/a$ and $\pi=1+1/a$ contradiction
$1-{2\over{\pi-1}}$ is algebraic implies that ${1\over{\pi-1}}=a$ where $a$ is algebraic, this implies that $\pi-1=1/a$ and $\pi=1+1/a$ contradiction