[กิตติ]

แปลงตรงส่วนคือ $(\sin 5^\circ +\cos 5^\circ+1)(\sin 5^\circ +\cos 5^\circ-1)$
$=(\sin 5^\circ +\cos 5^\circ)^2-1$
$=2\sin 5^\circ \cos 5^\circ=\sin 10^\circ$

$\sqrt{3}\cos 50^\circ -\sin 50^\circ $
$=2\left(\,\frac{\sqrt{3}}{2}\cos 50^\circ -\frac{1}{2}\sin 50^\circ \right) $
$=2\left(\, \cos 30^\circ\cos 50^\circ -\sin 30^\circ\sin 50^\circ \right)$
$=2(\cos (30^\circ+50^\circ))$
$=2\cos 80^\circ =2\sin10^\circ$

ข้อนี้ตอบ $2$