How to find the minimum value (0) of (2-sinx) / cosx

How to find the minimum value (0) of (2-sinx) / cosx

Let y = (2-sinx) / cosx = (sinx-2) / (- cosx-0)
Then y can be regarded as the slope k of the line AB between a (SiNx, - cosx) and B (0,2),
The locus X '= SiNx, y' = - cosx, 0 ≤ x ≤ π / 4 of point a is a part of the unit circle in the fourth quadrant
It is easy to know that when a (√ 2 / 2, - √ 2 / 2), the minimum value is obtained, where y = (2 + √ 2 / 2) / (0 - √ 2 / 2) = - 1-2 √ 2